I've read similar things on the warrior's forum at worldofwarcraft.com....

What your priest forum is talking about is damage avoidance --- blocks, parries, avoiding critical hits.  He's not really talking about mitigation (less damage taken from the same hit) even though it is a side-effect.

To my basic understanding, talent spec affects your DPS vs agro/fight-control, not specifically avoidance (although there are exceptions, which increase block and parry rates).  (i.e., protection specs increase your agro-gaining (in defensive mode), armor, shield effectiveness, stun ability, and similar abilities.)

According to what I've read, avoidance becomes key when tanking end-bosses and in Molten-Core-type dungeons; +400 defense, 5000+ health (before buffs), and similar things are key for the main tank (which is why the -33% on +defense in patch 1.7 has so many warriors upset -- harder to hit the magical +400) -- with lower numbers, a warrior takes so much damage that he can't really survive being the focus of raid-instance boss mobs, no matter what healers do.

Let's give an example:
Back when I was a brand-new 60, I joined Red in an UD Strathe 5-man.  The Baron (final boss) has mortal strike (tier-7 warrior talent in the arms tree).  He hit me with it at least once each time we attempted to take him down.  One of those times, his mortal strike criticalled.  Over 2400 damage taken in a single hit when my health was only ~5000 and i'd already taken several 600+ hits from him -- i was dead so fast I wasn't sure what had happened.

In theory, if I'd had +400 defense, the Baron would not have criticalled me (or at least, it would have been much less likely).

Thanks for your input Seeker(Sabre).  What you say seems to make more sense.  The original poster did mention that skill was a key thing that made a great tank, but I was wondering what he meant about gear.  I realize that warriors are a very gear-dependent class, but I was thinking more about fight management in general.  I was not thinking about the specific case of fighting a powerful raid bosses.  In those cases where someone is tanking a single super hard hitting boss, maxing out the defense stat on items makes a lot of sense.

Just general "tanking" abilities seem to me like they would be more influenced by player skill first and then by spec.  Sure some gear focused on certain stats might help.  From my perspective as a squishy caster/healer, I apprecite battle management.  If the warrior can keep the mobs mostly on themselves, I rarely run out of mana or die.  I only run out of mana during fights when the mobs break loose and I have to start healing 4 or 5 people, most of which are leather and cloth types.

There is really nothing a player can do to intervene with skill when you get smacked with a 2400+ point critical from a boss that is already doing 600+ points a chop.  Yeah, in those situations the +400 defense gear *would* make the tank.  Nothing else is going to save them and the group.

I also see why Warriors are comlaining more about the gear nerf.  It still only seems like a big problem for those high-end bosses though.  That constitutes what? maybe less than 3% of the games content though.  Bosses will just be much more of a challenge and accomplishment.

yes, but (for me so far), + defense really isn't all that easy to find.

I've never seen it on greens, only blues.  It's probably on purples, but I don't have any purples....

Granted, I've got a trinket w/ +200 (133 after 1.7), but the other items i have are +20/30 -- it's going to take quite a few items to get there --- which means that my armor/weapon options are going to be a lot more limited....

I agree 100% with this theory. I've got a 55 warrior on another server, and flipped back and forth between 100% prot. spec and 31 arms/prot spec. I've come to learn it's not really the talents so much as the damage mitigation (either through outright avoidance or lowering of actual damage) that makes you an effective tank. Once you can establish aggro successfully and keep it, it's all about healer effeciency. The problem with the protection spec I think is that none of the deep-tree talents really enhance your defensive abilities. I'm talking anything below the 20-point talent mark, which would be unobtainable with a 31 arms or 31 fury build. Sure, there's a nifty stun (which most high-end stuff is immune to), and a shield slam which causes massive aggro, but if you're already maintaining aggro, there's no real reason to add more. The only talent I'd consider deep-tree protection spec would be the 10% damage increase to 1h weapons. But even then, you get so much more damage out of a 31 arms build with MS, that the choice (at least for me) becomes clear. My planned spec is 31/5/15.

As for greens with +defensive, they are out there. I've found a number of them, mostly on shoulders or cloaks. They range from +3 - +12 defense, and that's the ONLY stat on them. Level ranges from 23-45 or so. Entirely not worth it at those levels IHO. When you start to get into the 50's, then you consider piling on more +defensive gear for the damage mitigation. I think this stat becomes more and more important as higher and higher level instances open up. Adding +10 stamina to your gear might seem feasable, but when enemies hit you for even 20 damage more than the ones in an easier instance, 100 life goes quickly. Whereas if you add even +5 defense, you increase your damage mitigation, and decrease the healer stress.

I'm gearing up my warrior now as we speak. Still low level (working on the BG rep), but got some nifty blue/purple gear waiting ( <3 for recently found Stockade Pauldrons ). I really enjoy the warrior class, especially when you know the success of a group can hinge on how well you play.

Actually Tiamant, there's plenty high-level stuff which both improved revenge and concussion blow will stun.  Granted, they don't shut down bosses, but they do a wonderful job of locking up "trash" mobs on the way to the bosses -- like the MC giants, which may be trash but hit harder than final bosses in 5-man instances.

Improved Shield Bash is a wonderful thing to keep certain high-lvl bosses (that stinking bat-lady in Zul'Gurub, for example) silenced when rogues and mages are busy doing other things (like dying -- her bomber-friends are EVIL).

Furthermore, the shield slam is very handy.  Its very much like a rage-expensive second taunt on its own timer; I have yet to slap something with it and not gain agro unless that something was already mostly dead and I was just showing up.  In other words, assuming you have the rage (which in higher lvl instances is NOT a problem), shield slam mob A off your healer, taunt mob B off your healer, and keep beating on mob B = 2 mobs leaving the priest alone.  Remember, all Taunt does is push you to the top of the hate list.  Its depressingly easy for a decked-out rogue to rip agro off you once the taunt "debuff" expires (especially if you miss once just as it expires) -- they hit for mad damage.  On the other hand, if you really want something to hate you, taunt then shield slam pretty much locks the mob onto you despite Mr. "uber-rogue's"  incredible DPS; as the tooltip states, shield-slam agro is "HIGH".

Finally, 15 points into protection isn't enough to get you all the talents I'd argue a MT of raid-instances needs:
    (toughness or anticipation: research of others show them to be comparable in damage mitigation, but spending 10 pts to get them both is way too expensive for the incremental increase of having both)
    defiance (there are places where you REALLY need that +% to agro -- you'll be living in defensive stance for the -10% damage)
    shield block (spamming shield block when priests are having mana issues helps them a lot -- especially when you're blocking multiple hits because multiple mobs are on you)
    last stand (30% of your health? we're talking 1500-1800 health to be added when things look dicey. granted, you're going to lose it in 20 seconds, but.....)

Until you get into the UBRS/ZG/MCs of the world (raid-instances), I'll agree with you -- don't worry about the upper tiers of the protection spec.  However, once you get there, if you really want to be a MT who is "all you can be", those painfullly-expensive talents actually start having purpose and making a difference.