From the original BC release their armor in bear for was reduced from 450% to 400%. Though they are still reaching the armor cap well before they get to the end game 25 mans.
Mangle in bear form was reduced in dmg. Swipe now has no extra threat modifiers save for the innate bearform mod.
Thats all I can think about right now.
Imo our real competition for tanking is coming from prot pallies now. Once they get geared and if they know what they are doing they are freaking incredible.
Warriors will still remain as the best raid boss tanks due to our innate abilites, but all three are more than viable.