Warriors as tanks

"Tanking" is the art of drawing the enemy's fire while the rest of the group kills it.

The signature role of the Warrior in PvE is that of the Tank. Basically a tank is the character who takes the brunt of the mob's damage, in the hopes that no one else in the group will take any. Warriors are best suited for this task for two reasons:
 * Warriors take damage more efficiently than any other class; i.e. given the exact same situation, a warrior will take less actual damage than any other class of character, due to the warrior's extra armor and blocking abilities.
 * Warriors have effective tools at their disposal for generating Aggro, thus keeping themselves the focus of all enemies in the encounter.

This article primarily discusses tanking by a warrior and does not give much advice on tanking by other classes, though others (e.g. Paladin, Druid) can certainly do so depending on the situation (non-Raid, non-high-level-Instance settings).

Why Tank?
The fastest, safest, and most efficient way through an instance, or any tough encounter, is through good solid tanking. Warriors naturally love wielding big flashy weapons and seeing big damage numbers over their enemy's heads, but the warrior's most valuable contribution to a group is not damage -- it is aggro generation and damage absorption.

Warriors have the ability to absorb, mitigate and/or prevent plenty of damage through their use of plate armour, their high health, the Defensive stance, and the Protection talent tree. This has three strong benefits to the healer(s) in the group. Most obvious is that because you take longer to die, the more time your healers have to heal you. This in turn increases the efficiency of their heals because they don't need to cast a healing spell until you will actually benefit from the entire spell (i.e. you are down by that many health points); thus you do not waste any of the mana that the spell costs. It also gives your healers the opportunity to use more mana-efficient heals, which are typically bigger and slower to cast. Finally, the longer the healer can wait before healing you -- and the less often a heal is needed, the less aggro the healers will generate for themselves.

On the flip side of the coin, a tank's ability to generate aggro is often the limiting factor for many DPS classes. This is particularly true for mages and warlocks who often lack aggro management tools, but even for rogues and hunters good solid aggro on a target can save them the energy/mana of feinting or feigning death. In all likelihood though, rogues and hunters are feinting and feigning and *still* running up against the ability of a tank to generate aggro. The tank's aggro behaves almost like a multiplier on the amount of damage other classes in the party (including other warriors) are able to do.

It is the combination of these abilities that makes such a big difference. By generating more aggro, the warrior can effectively increase the damage output of the rest of the party, and by mitigating more damage, the tank can put off the moment when the healers run out of mana and people start dying. In a well balanced group this will result in an incredible increase in damage over what the warrior could ever hope to do on their own.

Simply put: A good tank means that every other member of the party can do more damage for longer.

Grabbing Aggro, and Holding it
Revenge is the ability that creates the most aggro, however it can only be used after a successful dodge, block, or parry. If revenge has not been lit up by a dodge, block or parry, a warrior can use Shield Block to almost guarantee it is available. On its own, Revenge is far and away the best means of converting rage to aggro. Even with the extra rage for the Shield Block, Revenge is still the most efficient aggro generating ability a warrior has and ideally should always be cooling down.

However, as Revenge is only usable once every five seconds and costs remarkably little rage, tanks are typically left with a significant amount of rage. Opinion is divided into two schools on generating aggro with this rage: those who prefer to Sunder Armor repeatedly and those who use Heroic Strike as their primary method of aggro generation. Sunder Armor can be used at any time and is on the global cooldown so it can be used repeatedly, draining rage quickly but creating a lot of aggro regardless of weapon type or enemy. With a fast weapon Heroic Strike can generate a lot of aggro, particularly against lightly armoured foes, but because the ability prevents the warrior generating rage through their own attacks it can be more difficult to generate sufficient rage. Both methods also result in additional damage on the target, either directly in the case of Heroic Strike or indirectly through the use of Sunder Armor.

What most warriors seem to overlook is the fact that Shield Bash creates quite a bit of aggro, almost as much as Sunder Armor. If your target is a caster save shield bash for spells worth interrupting, for example heals. However, even when used on a non-caster it is a decent skill for aggro generation worth mixing in with the Revenges, Sunder Armors and Heroic Strikes.

Using a Main Assist to help the tank
Efficient and good tanking is not only up to the tank, it is a group effort. The group can help the tank's ability to tank or make it utterly impossible. Consider the following scenario. We have a party of five, one tank, one healer and three DPS characters. In a given pull of three mobs the three DPS characters pick one mob each and start attacking them, the healer tries to keep everyone alive. In this situation it is impossible for the tank to get and keep the aggro of all the mobs, as he is forced to out-aggro all three DPSers on three different mobs. In addition the total lifespan of the mobs in the fight will be unnecessarily long (since they may all die at the same time instead of one at a time if the firing was focused on one mob at a time), meaning the total damage the party have to endure is larger and more healing is required, so the risk of the healer getting aggro increases.

The solution to this is using a main assist (MA). The idea of a MA is that one person is responsible for deciding which mob the party is currently killing and all party members assist that player to attack that same target. The classes best suited for this are rogues and hunters. Any character that is healing, cleansing or may have to recast crowd control spells during the fight are not good options. The MT should not be used as MA, since s/he needs to hit all mobs to keep aggro. As soon as the current target dies, the MA should already have switched to the next victim so the rest of the party can hit their assist button and keep going. Advanced tip: if you've got enough rage you can hit Heroic Strike and immediately hit Sunder Armor. Heroic Strike does not trigger the global cooldown so they basically both go off at the same time. Keep in mind that the Heroic Strike will prevent you getting rage from that next swing and both Heroic Strike and Sunder Armor are expensive, so this is for 50+ rage situations. This is a tricky, but extremely powerful technique in situations where you have a lot of rage. Also note that neither Shield Block nor Cleave trigger the cooldown either. Cleave and Heroic Strike are mutually exclusive, but Shield Block and Heroic Strike aren't.

If the group is using a MA and not using any area of effect spells (including the Hunter's Multi-Shot) the chances for the tank to retain aggro of all mobs is very much increased. With this setup the tank can focus mostly on the current target and only cycling through the other mobs to add a few Sunder Armors now and then. On those mobs the tank is only competing with the healer for aggro. Nobody else can possibly get their aggro.

Taunt
Though frowned on, this is one of the most useful abilities of the warrior and must be used wisely and without hesitation. If a mob attacks one of your cloth wearers, taunt the mob off him and increase your aggro to the extent that this mob will focus on you until his death! Learn how taunt works, use it whenever it is needed and hope that the party you are with will learn how to work without it.

How does taunt work? It immediately gives the warrior the same aggro value as the highest character with aggro at the moment AND for three seconds it MAKES the mob attack you and you alone. You have to use these three seconds well so that after those three seconds the mob will stay aggroed on you.

The problem is that the mob remembers who he was aggroed on before you taunted him and he will return to him once the three seconds is up. The rule, as far as Kenco found out, is that the mob aggros a new target when that target has 10% more aggro then the current one.

So once the taunt is working, the warrior has three seconds to gain 10% more aggro. To do that, you will usually use the Revenge/Sunder Armor combos.

So, when the mob attacks your priest/mage, taunt him, and use Revenge/Sunder Armor immediately to gain 10% aggro. At the same time ask the priest/mage not to do anything, so you won't have to create enough aggro to overcome their extra damage/healing.

The mark of a truly great party is that you will never see a Taunt debuff on a mob while in his group. It can be effective, however, against mobs with complicated knockback, e.g. Molten Giants in Molten Core, and Teremus the Devourer in the Blasted Lands. These mobs have an ability that knocks the warrior back about ten yards and clears part of the agro that the warrior has generated. This puts the warrior in a position where he cannot use any of his aggro-generating abilities, as he is out of range. If the warrior's aggro has been sufficiently reduced these mobs then proceed to go to town on the nearest mage or Priest, often causing death. Timed correctly, taunt can prevent this. If used immediately after the knockback connects, while the warrior is in the air, the mob will follow the warrior through his knockback path, and be in range for all aggro-generating abilities upon landing. In this and other situations taunt must be used.

At most other times it should be saved for emergencies, such as aggro on the main healer. Other times taunt is useful include Lava Annihilator fights in Molten Core. Lava Annihilators don't even have a hate list; targets are chosen completely at random. Taunt, however, forces them to attack the taunter for two seconds, and Mocking Blow will give six seconds of cloth wearers not being hit. Taunt can be useful, but it is often given too much importance by tanks; it is at best a stopgap measure, not truly an aggro holding ability.

Primary tank
The point of the primary tank (also known as the main tank) is not to deal damage, but to take it. It is also a tank's job to gain aggro and keep it. While one way of doing this is to deal damage, usually other party members will be dealing more pain than the warrior, so the tank should focus more on using abilities to hold aggro than damage. This being the case, primary tanks are almost always best served by using a shield and a one handed weapon, particularly those that boost defense and Stamina.

If you want to make tanking the purpose of your warrior's existence, the Protection talent tree is your friend, with Arms as a secondary.

Most warriors tend to prefer a more damage dealing approach while leveling up to 60, since the extra bonuses to defense that the talent tree gives isn't very notable until higher instances. Therefore most warriors tend to their daily business with a two-handed weapon, but always keep a shield and a one-hander handy in their backpack. Gear with +Defense and +Stamina is the trademark of any equipment that a primary tank uses, the more defense a tank has the more chance they have to dodge, parry, block, resist critical strikes and resist crushing blows and the more stamina, the more damage they can endure, giving the healers time.

"Easy to get" primary tanking gear with defense at level 60:


 * Helmet - Enchanted Thorium Helm or Golem Skull Helm
 * Necklace - Medallion of Grand Marshal Morris
 * Shoulders - Stockade Pauldrons or Bulky Iron Spaulders or Stoneform Shoulders
 * Back - Cloak of Warding or Redoubt Cloak
 * Chest - Ornate Adamantium Breastplate or Kromcrush's Chestplate
 * Bracers - Fel Hardened Bracers or Bracers of Heroism or Runed Golem Shackles
 * Hands - Force Imbued Gauntlets or Stonegrip Gauntlets
 * Belt - Stalwart Clutch or Belt of Heroism
 * Legs - Legplates of the Eternal Guardian or Legplates of Heroism
 * Feet - Boots of Avoidance or Master Cannoneer Boots
 * Rings - Ring of Defense, Hardened Stone Band or Band of the Ogre King
 * Trinkets - Demon's Blood or Force of Will

Secondary tank
The secondary tank (also known as the off tank), in contrast, is there to do damage. They are also there to intercept mobs that break away from the primary tank and they care more about buffing the group and, in particular, protecting the party's healer. Secondary tanks tend to go for armor similar to a primary tank, but forgo a shield in lieu of a two-handed weapon.

Considerable secondary tanking gear at level 60:
 * Helmet - Lionheart Helm
 * Necklace - Emberfury Talisman
 * Shoulder - Spaulders of Valor
 * Chest - Breastplate of Valor
 * Belt - Omokk's Girth Restrainer
 * Bracers - [Vambraces of the Sadist]] or Battleborn Armbraces
 * Gauntlets - Reiver Claws or Stronghold Gauntlets
 * Legs - Eldritch Reinforced Legplates
 * Trinkets - Blackhand's Breadth

An interesting tactic for a mid- to high-level Protection warrior while soloing – build up 60 or 70 rage, then switch to the slowest two hander available (Corpsemaker is a good one for low 30's, Whirlwind Mace is an amazing one for as soon as you can get it), hit Concussion Blow, and then use Slam two to three times. You'll deal out full damage in less than half the time.

DPS Tanking, and tanking out of Defensive Stance
A generally frowned upon method of holding aggro, it can however be useful for lower-level encounters, if you're the only warrior in group and are DPS-specced (and geared).

If you're not convinced on the idea, remember all those rogues and hunters stealing your aggro purely with their damage output. If they can do it, you can do it too.

The key to successful DPS tanking (and not being thrown out of the group after first wipe) is skillful Stance Dancing. You will have to switch stances much more often (and faster) than in prot version. It is a difficult style of tanking, but it can be fun, and it doesn't require you to respec and/or use inferior gear in case your main role in game is being a PvP meat cleaver.

It is good to start the pull in Defensive Stance, this way you gain initial aggro. You start as regular tank, with few Sunder Armors or Revenges, and then switch to Battle or Berserker (depending on how well you work with your healer) Stance to start dealing heavy damage.

Berserker has the disadvantage of decreased damage mitigation and aggro generation, but it allows several very useful abilities for a tank. First off all, it allows simple multiple-target tanking: spamming Whirlwind helps keep aggro off casters a lot. Berserker stance is also necessary for encounters with mobs who fear - it's actually more useful if MT stays in Berserker stance while fighting Troll Berserkers in ZG than it would be for him to stay all in Defense. And if you're still feared off, you can use Intercept to quickly get back to your target. Another disadvantage is that you only generate rage from damage you deal. However, if you're going to DPS tank, I recommend Berserker over Battle.

Battle Stance is good for generating rage, and few situational abilities. Tap Sunder Strike as soon as it's lit, and then switch to Defense - for 15 seconds you'll keep aggro on two mobs. If you have a high dodge rate, don't be afraid to use Overpower whenever it's available. Apart from that it doesn't really have any advantages over Defense Stance - since your reduced damage generates more aggro, it evens out - and Defense gives you better abilities.

Switch to Defense whenever you feel like you're about to lose aggro. With some experience you can tell when it's about to happen.

Tanking with 2h weapon? Yes, it can happen, if you can rely on your healer, and your group has high DPS output as a whole. When fighting casters forget about shield altogether, unless you have some extra resistances on it: armor is useless against magic anyway, and extra damage from 2hander helps you beat down the caster fast. Use Pummel instead of Shield Bash. With good group, you can even try to go through Stratholme using shield only for boss fights.

Other tips:
 * Stay near the top of the damage meters. If you're constantly outdamaged, forget it and go Defense. You can't DPS tank if you have too low DPS.
 * Look out for opportunities to Taunt. You will give your casters and healers a short heart attack, as the mob races towards them, but a single taunt will get you back on the hate list. Once you lose aggro, you just can't snap it back with pure damage. Ask Paladins.
 * If you're DPS specced and have good weapon, use Heroic Strike instead of Sunder. It costs roughly the same, it will generate similar amount of aggro and will hurt the mob a lot.
 * DPS tanking is a matter of trust. Do it only if your group knows you and allows you to do it. Plus, healers hate it.
 * Do NOT ever try to DPS tank in raid instances. It just won't work. However, use extra abilities given by Berserker Stance where necessary.

=Aggro Skills By The Numbers= Cop on The Steel Warrior Forum posted the following set of aggro skills and their relative aggro ratings.

Formula used in #5: [ ((HateMin + HateMax)/2) + (((DamageMin + DamageMax)/2) * (1-DamageReduction) * 4.0 ] / RageCost
 * Skill Name
 * Rage cost.
 * Listed damage before armor is applied, taken directly from the tooltip.
 * Attached or "innate" hate. This is completely independent of the damage the skill produces. It is purely a hidden "bonus blast" of hate when the skill lands successfully.
 * perks: qualitative reasons to use a certain skill
 * negs: negative stuff about the skill
 * Total hate including damage under varying armor levels.
 * Hate per point of rage. This number indicates efficiency if you're wondering how best to dump your rage. Once again, it does include damage.

Revenge

 * 5 rage
 * 64-78 damage
 * 1200-1250 "innate" hate
 * perks: very high efficiency, chance to stun with talents, fair damage for rage cost
 * negs: unreliable, and often requires use of a 10 rage skill to allow its use
 * 0% Damage Reduction
 * 1510 total hate
 * 302 hate per point rage


 * 25% Damage Reduction
 * 1440 total hate
 * 288 hate per point rage


 * 50% Damage Reduction
 * 1370 total hate
 * 273 hate per point rage

Shield Slam

 * 30 rage
 * 450-550 damage
 * 925-975 "innate" hate
 * perks: 50% chance to dispel 1 magic effect, good damage, much improved efficiency as of test patch 1.7
 * negs: efficiency is very dependent on armor
 * 0% Damage Reduction
 * 2950 total hate
 * 98 hate per point rage
 * 25% Damage Reduction
 * 2450 total hate
 * 82 hate per point rage
 * 50% Damage Reduction
 * 1950 total hate
 * 65 hate per point rage

Thunderclap

 * 20 rage
 * 103 damage (in battle stance, hate modifier of 2.25)
 * 200-250 "innate" hate
 * perks: 10% attack rate debuff, affects up to 4 targets
 * negs: must be used in battle stance, breaks CC
 * 0% Damage Reduction
 * 460 total hate
 * 23 hate per point rage
 * 25% Damage Reduction
 * 400 total hate
 * 20 hate per point rage
 * 50% Damage Reduction
 * 340 total hate
 * 17 hate per point rage

Sunder Armor

 * 12 rage (15 without talents)
 * no damage
 * 1025-1075 "innate" hate
 * 1050 total hate
 * 88 hate per point rage (70 without talents)
 * perks: lowers target armor, no cooldown
 * negs: Some claim aggro is spotty with sunder armor when the debuff gets pushed off, when the debuff expires, or when it's stacked more than 5 times. My findings suggest none of this is true.

Shield Bash

 * 10 rage
 * 45 damage (ignores armor)
 * 725-775 "innate" hate
 * perks: spell interruption, silences for 3 seconds with talents, good high aggro skill
 * negs: long cooldown, spamming of the skill means it won't be available when needed
 * 930 total hate
 * 93 hate per point rage

Demoralizing Shout

 * 10 rage
 * no damage
 * 165-185 "innate" hate
 * 175 total hate
 * 18 hate per point rage
 * perks: attack power debuff, unlimited targets
 * negs: very low rage efficiency

Heroic Strike at 3 rage per swing

 * 15 rage (18 without talents)
 * 138 damage
 * 590-630 "innate" hate
 * perks: good damage, cooldown is weapon speed, doesn't interfere with global cooldown, instant attacks can be used while waiting for it to fire.
 * negs: hinders rage production from attacks
 * 0% Damage Reduction
 * 1160 total hate
 * 77 hate per point rage (65 without talents)
 * 25% Damage Reduction
 * 1020 total hate
 * 68 hate per point rage (57 without talents)
 * 50% Damage Reduction
 * 890 total hate
 * 59 hate per point rage (49 without talents)

Heroic Strike at 7 rage per swing

 * 19 rage (22 without talents)
 * 138 damage
 * 590-630 "innate" hate
 * perks: good damage, cooldown is weapon speed, doesn't interfere with global cooldown, instant attacks can be used while waiting for it to fire.
 * negs: hinders rage production from attacks
 * 0% Damage Reduction
 * 1160 total hate
 * 61 hate per point rage (53 without talents)
 * 25% Damage Reduction
 * 1020 total hate
 * 54 hate per point rage (47 without talents)
 * 50% Damage Reduction
 * 890 total hate
 * 47 hate per point rage (40 without talents)

Cleave at 3 rage per swing

 * 23 rage
 * 50 damage (110 with talents)
 * 370-420 "innate" hate
 * perks: hits two targets, cooldown is weapon speed, more than doubled efficiency if a second enemy is in frontal arc, fair damage, doesn't interfere with global cooldown
 * negs: hinders rage production from attacks, is on-next-attack so it prevents the use of other skills if you wait for it to fire
 * 0% Damage Reduction
 * 590 total hate (830 with talents)
 * 26 hate per point rage (36 with talents)
 * 25% Damage Reduction
 * 540 total hate (720 with talents)
 * 23 hate per point rage (31 with talents)
 * 50% Damage Reduction
 * 490 total hate (610 with talents)
 * 21 hate per point rage (27 with talents)

Cleave at 7 rage per swing

 * 27 rage
 * 50 damage (110 with talents)
 * 370-420 "innate" hate
 * perks: hits two targets, cooldown is weapon speed, more than doubled efficiency if a second enemy is in frontal arc, fair damage, doesn't interfere with global cooldown
 * negs: hinders rage production from attacks, is on-next-attack so it prevents the use of other skills if you wait for it to fire
 * 0% Damage Reduction
 * 590 total hate (830 with talents)
 * 22 hate per point rage (31 with talents)
 * 25% Damage Reduction
 * 540 total hate (720 with talents)
 * 20 hate per point rage (27 with talents)
 * 50% Damage Reduction
 * 490 total hate (610 with talents)
 * 18 hate per point rage (23 with talents)

Bloodrage

 * 20 rage generated (25 with talents after patch 1.11)
 * 337 damage to a level 60 player
 * 325-345 "innate" hate
 * perks: generates a good amount of rage
 * negs: the mob must be focused on you for it to create aggro, takes hp, less with talents

=Tanking Guide= GraniteMG posted the following tanking guide on Steel Warrior Forum:

Aggro Generation
The number 1 complaint I've heard about warriors is aggro generation. Hunters complain because their pets hold aggro better than most warriors, healers hate healing themselves more than the tank, etc. In 60 levels of duoing with a hunter, even with growl on at times, there's no point where a pet should be able to keep aggro from a warrior.

Aggro based skills
see above


 * Revenge
 * Shield Bash
 * Shield Slam
 * Sunder
 * Heroic Strike

Now Blizzard went and labeled the skill so that some of them say high aggro, moderate aggro, etc. This was a great idea, but the problem is... they lie to you! Heroic strike is not high aggro; it's decent, and I use it here and there, but it doesn't compare to shield bash which is remarkably not listed as having extra aggro.

The order in which I prioritize skill use is the order those abilities are listed in. Revenge will always be used if its up, it generates remarkable amounts of hate, and at 5 rage to boot. Shield Bash is the same thing, I use it every time it's refreshed for extra hate. Not everyone will have shield slam, but due to the hefty rage cost it's situational anyway. It's phenomenal when fighting 1-2 mobs, and I'd use it every refresh in those cases, but when trying to keep aggro from 3-5 mobs I only use it when I'm taking enough damage to have excess rage. I use sunder after that. I have a theory that after you have 5 sunders on a mob, they don't produce as much hate. It's just a theory, but it's one I stick to. I use heroic strike to add some damage, but it doesn't get used often unless I know I already have hate established via the other skills.

Most people don't have trouble keeping aggro on 1 mob, especially if you stick to what I listed above, so going to move on...

Multiple Mob Pulls
Myth: Spamming Demoralizing Shout is good for holding AE aggro. I have max improved demoralizing shout.

Fact: I can attest to it being absolute garbage for aggro.

If you need to hold aggro on multiple mobs, you have to be attentive and intelligent about it. I see it as fortunate that being a good tank is not a lazy job; others might not. Here's what an average pull of 4-5 mobs is like for me:


 * Pull 4 mobs (I generally pull, though in a tough situation a hunter might be better for pulling)
 * Shield Bash Mob1
 * Demoralizing shout for Contact Aggro with Mobs 2-4
 * Revenge Mob1 (I generally use 2 abilities on the first mob before locking in aggro with the others, otherwise I'm sure to lose aggro if there's a rogue around)
 * Sunder Mob2
 * Shield Bash Mob3
 * Sunder Mob 4
 * Revenge Mob1
 * Sunder's not really incredible aggro, so I'll hit mobs 2-4 each with a shieldbash/sunder/revenge again then stay on the main mob. If Mob1 is dead, I'll stick to mob2 to maintain aggro from the DPS.

If it's an AE situation, you'll have to switch targets constantly. When we do AE things, I generally try and grab the 3 hardest hitting mobs and keep them on me. Trying to keep any more than that is just unreasonable when mages are spamming Arcane Explosion, and warlocks are going nuts with hellfire.

Try it out, get use to it. Seems like a lot of work at first, but eventually it becomes second nature and your groups will love you for it.

Gear
You'll hear varying opinions on gear. Some people will stick to just armor and stamina for tanking, though in WoW, I don't generally like to. Unlike Everquest, more hp does not always equal better tank. There's no hp in this game, and healers will be adjusting to burst DPS regardless. Most of the time healers will ONLY be using their flash heals and Power words. Because of this, I believe you can't really devalue avoidance as a means of damage mitigation. I run about 35-37% avoidance, depending on buffs. That's 35-37% less healing I need. People might say avoidance is too spikey, but the alternative is just taking all the damage anyway. Avoidance can be spikey, but it offers mana breaks to your healers, as long as your healers are on the ball and talented, avoidance is always a boon. Healing in World of Warcraft isn't the automated push button and walk away it was in Everquest. (Trust me, the healers enjoy this fact too.)

That said, this is how I evaluate gear for tanking:

Stamina
Stamina is bread and butter. Get as much as you can, but (and this is a big but!) not at the cost of sacrificing avoidance or mitigation. Stamina is very important to a point, that point is being able to survive a round of max damage from a mob. After that, stamina simply acts as buffer for your healers to give them breathing room. Efficiency is better than buffer!

Armor
Mitigation is the best source of damage reduction you can get. It's consistent so your healers love it, that alone makes it better than avoidance by a small margin. An equal amount of mitigation will always be just a little bit better than an equal amount of avoidance.

On that note mitigation tends to have "diminishing returns". This is a tad deceptive, as it scales in a different way. The % reduced may not be as high per point of armor as you get more, but think about this: Going from 0% to 50% means you're taking half as much damage as when you have 0% reduction, but going from 50% to 75% also means you're taking half as much damage as if you have 50% reduction.

Sadly, the gear currently available to Warriors and Paladins simply doesn't contribute enough to their Armor rating to make a crucial difference. The amount of extra mitigation brought by even the best plate gear with the highest Armor values simply cannot come close to matching the amount of extra avoidance available from the right plate gear sets. Druids, on the other hand, with their +360% Armor bonus in Dire Bear form, can raise their Armor value significantly higher.

Avoidance
1% Dodge, 1% Parry etc. These are all great to have. Value 1% avoidance just under 1% mitigation, and you'll be doing good for yourself. The main reason I value it even this high is because of the effects it avoids. Dodging an Onyxia knockback isn't too shabby!

Agility
A bonus of 20 agility is always going to be better than 1% dodge straight up for one simple reason. DPS does matter when tanking. Don't let anyone tell you different. The skills are what make you as a tank, but doing decent dps keeps your aggro up there. The damage you do scales with equipment, but the aggro generated by skills doesn't! So don't try using a 20dps mace just because it gives 7 defense; it's just not worth it.

Defense
The best way to look at defense is to see it as 1.2% avoidance per 10 points. If you value defense solely for the avoidance it provides you'll generally get enough defense to avoid critical hits anyway. 10 points of defense = +0.4% Dodge/Parry/Block/Mob-missrate/mob-critrate.

This last point, the mob's crit rate, is perhaps the most important. Defense is the only ability in the game that reduces the chance of receiving a critical hit. While getting hit less often will put less of a strain on the healers over the long haul, avoiding the "spike damage" of a critical hit will save the tank's life if her health doesn't happen to be near full at the moment.

Defense all around is fantastic.

Block
Increasing your Block chance is useful when you understand how to use it right.

By itself (for most well-geared warriors in most situations), a successful Block will negate some 100-300 hp from an attack which usually does some 500-1000 damage. It is a good mitigation, and over the course of a full boss fight, you might block thousands of damage. But as can seen from these numbers, it's not a really earth-shaking ability, and should not concern you too much. Get what you can, and don't gimp yourself over this.

Having a high Block chance in high-end raids is AWESOME, and a MUST for tanks! (This is true ONLY for PVE in level 60 raids, 20+ people - the following is not true/useful for pvp, or for instances of 5-10 people.)

The main problem with high-end raids are mobs and bosses that can one-shot (or two-shot) tanks. If they crit/crushing blow the tank, at best, the tank will be in very low hp; at worst, it's a wipe.

Due to the table-based nature of the way WoW resolves attacks, an attack that is blocked cannot be a crit or a crushing blow. Since theses attacks are usually a raid-wipe, a good tank will try to have 25% block chance, and with Shield Block she will have a 100% block chance. So if you're going to tank in high-end raids, work on your block.

Note: Defense adds to block chance. For each point of defense, you add 0.04% to your block chance. So, through high defense, you will block more often.

Note 2: Each time an attack is blocked, Revenge becomes available for use (if it's not on cooldown).

Onyxia
Onyxia isn't as painful as you might expect. Generally a paladin can heal through the standard melee on me and a priest can cover the burst dps. It seemed like they could do that infinitely. Generally I run as much FR on Onyxia as possible. I've worked hard on my Fire Resist gear, and while it isn't perfect yet, I sit at around 260 Fire Resist buffed as of writing this. For Onyxia that's a huge boon, I resist 75% of her fire breaths, and that's a huge chunk of her DPS. They hit for 3600, and she uses them often.

The Process: When tanking Onyxia, you'll head in, take a swing at her while you move in front of her, then turn around and start building aggro. The entire time you'll be backpedaling and she'll eventually throw you. The position you want her in is fairly close to the north wall, dead center. Positioning her is the challenge of the raid.

Onyxia is the most attention-intensive mob I've ever tanked. If the tank slacks, the raid wipes. She knocks back often; each time she does, she tends to de-aggro you some, and if you don't move back to her immediately she'll move up to you. That's bad! You want her a good 20 feet away from the north wall, so that when she uses her knock-back you hit the wall and run back at her. If she's too close when she uses her knock-back, you'll slide along the wall and then she'll kill half the raid with a poorly timed fire breath.

So to reiterate, you CAN NOT wall her. You can get right underneath her feet if she happens to get close, to give yourself some more breathing room... and a trick on re-positioning... she's scared of mice. What I mean by that is if you run up to her feet, then slowly nudge forward, and forward, eventually she'll turn around and take a few steps back and face you again. This is perfectly fine even though the raid might freak out. Her back isn't really to the raid, it's just the animation, there's no risk of tail swipes or anything like that from everything I've seen.

Once you've got her in a good position you have to constantly run back at her and cycle your abilities. It's an intense job.