There are a lot of huge changes in the expansion though. Warrior tanks are worried they won't be useful anymore because their big niche (surviving crushing blows) was given to all tanks. Paladin tanks are concerned because better AE threat is being given to all tanks. Death knight tanks are worried that they are going to get nerfed because of the damage they're doing. Druids are worried that they won't have the armor they are used to, and might be inferior tanks because of it. Almost every class is worried that their unique raid buff won't gaurantee them a spot in the raid any longer. We're worried about pulling it all off. :)
The thing of it is, that was never the warrior's niche in the first place. With shield block having two charges in 5 seconds, warriors were almost guaranteed to take a crushing blow every so often thanks to haste or dual wielders or anything that has more than 2 attacks every 5 seconds. Paladins, with their holy shield having 8 charges every 10 seconds, were almost guaranteed to never take a crushing blow in that time unless lag or silence was in play. Of the three tanking classes, warriors were the middle ground between no crushes and always being crushed.
Heck, this is why druids were favored over warriors on Morogrim - because a warrior would quickly be depleted of shield block charges and could easily take a crush, a druid was better simply because if you're going to take a crush, you might as well take as little damage as possible anyway.
This is the sort of thing that makes me really concerned about the direction of tanking in WotLK. I know the devs are smart, and they're good, but they have some bizarre notions of what the classes actually did in the past. The devs seem to believe that feral druid tanking in BC was somehow bad and that a bear couldn't MT things on progression, yet feral druids are advantaged in some way on every single encounter in Sunwell but one, and the top guild in the world (SK-Gaming) has two feral druids as their main tanks. The devs believe that a warrior's niche was the inability to take crushing blows, but the warrior niche in TBC was outstanding top-end threat combined with being the best tank against magic-based bosses. A paladin doesn't care about other tanks getting their AoE abilities, because who cares who is requested for 5-mans? They care about being able to MT, and for that they need oh shit abilities, better threat cycles with overlapping cooldowns, more threat on non-undead/demon types and better itemization characteristics that share both mitigation and threat - and in the beta they've gotten most of that.
Would people be interested in seeing a patch 3.0 Paladin tanking tree? I don't want to do one for WotLK, but a TBC one seems like it might be worthwhile.