Lvl 71 Prot Warrior. I've tanked everything up to WotLK fine. Utgarde Keep was easy also. I tried tanking the Nexus and everything is hitting really hard. The healers are having trouble keeping me up. Any advice? Have I specced wrong? I've a DK tank I lvled precata and throught cata DK tanking is easy.. Not sure what stats to go for. Dodge/Parry etc..
You're saved in your level 70 PvP gear, which I hope is not what you tank in. If your gear is crappy or doesn't have much for defensive stats, try getting the level 70 Cobalt set crafted. It has tons of dodge and stamina, and isn't going to break the bank.
I'm no expert on Warriors, far from it, however I can definitively tell you that Bastion of Defense is must-have-maxed talent. You're probably getting critted by mobs, which hurts even at lower levels.