To those mentioning never seeing a +holy damage item, we had Drape of the Righteous drop for us off karazhan trash last night.

Drape of the Righteous
Back
85 Armor
+11 Intellect
Equip: Restores 6 mana per 5 sec.
Equip: Increase the damage done by Holy spells and effects by up to 40.

With no stam I doubt it'd be any help for tanking, but the stat is out there and may be further itemized in the future.

As far as tanking goes, I've tanked all 3 coilfang instances, blood furnace, ramparts, and black morass (all heroic), karazhan up to the chess event, the High King, and I've been our tank for most of our Gruul attempts.

Originally we had a prot warrior tanking Gruul, but (and I might just be terrible at this) I was unable to remain 2nd ag through the whole fight to take the other attacks. If I'd start attacking when the DPS starts I'd pull aggro off of our MT with nothing but white attacks and a mangle. If I'd wait longer, he'd start to one shot rogues and our fury warrior before I had hate built up.

I ran a KTM yesterday through Karazhan while main tanking most of it. Nearly all of the mobs there are unbleedable, but even with swipe spam instead of lacerate I was able to average around 700 TPS. On Moroes, who is bleedable, I reached numbers above 1100 TPS. Of course it would drop when he vanished but it wasn't difficult to get it back up to that level. I'm not sure the length of time KTM uses to find an average though. In my current tanking gear, completely unbuffed, I've got 21777 armor, 11568 HP (582 stam), 409 defense (140 rating), 30.28% dodge, 1470 AP, and 26.75% crit. I realize I'm not uncritable at the moment, and that's the next thing I'll be working on. Some of my numbers, especially armor, could be much higher also but I never asked to be a tank. While leveling I never looked at armor values so I have none of the high armor greens or umberhowl's collar, as I expected to go back to resto after reaching 70.

Talking with the old MT of my guild, I mitigate more with armor, I avoidance is slightly lower, my stamina trumps his by a few thousand (I was sitting just above 19k our last High King kill... kings, mark, fort, commmanding shout, blood pact, and flask of the titans I believe... the flask was not my idea), my threat surpasses his, and he doesn't stand a chance to coming close in damage. At the moment, at least for us, druid tanking has replaced the "general tank" position, pushing warriors down to a "specialized tank" role.

I had this for a long time after getting it in a Maraudon run:
http://www.wowhead.com/?item=17741

Not the best item, but certainly interesting.

Hmm...I guess I misunderstood the attack roll. I had this impression that I needed to have 100% block (achievable by warriors without too much trouble?). Apparently not.

In any case, I do get crushed with Holy Shield being spammed (~5 times by Curator the other night I think), and my guess is thats because Redoubt isn't up. I rarely use all my Redoubt (or HS) charges, and it tends to fall off from dodges/parries.

Well, point taken - but the Stam differential seems to be the hardest thing for a paladin to make up (defense cap/dodge/parry is easy enough). I think I'm going to hold off trading block rating for stam on a primary tanking set, stick with a higher HP pool until I can snap up the Nightbane chest/Moroes belt, which provide a good mix of stats.

Ye, many people say 25% block must be achieved, and the rest is done by shield block; which is not correct with what we believe right now. 25% total avoidance is needed to knock the crushes off by shield block, and any naked protection warrior should have it.

On the topic of threat, I wrote a relatively small C++ utility to estimate warrior threat generation (because that's what I'm familiar with) under various circumstances, taking into account things like DPS stats, target armor reduction, skill use rates, threat and damage modifiers, etc.

It looks like, for a warrior with 1000 AP / 10% crit / 0% hit, with a 71 dps 1.6 speed weapon, using a Revenge -> Shield Slam -> Devastate -> Devastate cycle with 3.5 Heroic Strikes per 6 seconds, on a target with 25% damage reduction, you're looking at 861 TPS. Upping that to 2000 AP / 25% crit / 5% hit, and you're up to 1123 TPS. Alternatively, keeping the initial stats but lowering it to a more realistic 1 Devastate per 6 seconds and no HS spam, and you're looking at 517 TPS. Optimal Arms warrior at 3.5 HS / 6s and Sunder/Revenge spam is looking at 471, and with no HS spam, only 242 TPS.

Take it at face value!