What do we have over other classes that requires that "extra work" as a balancing measure? Threat? The threat gap between warriors and other tanking classes has been slowly eroded to where we're all quite close. And it's irrelevant anyway as long as your tank is doing 30% more threat than your best DPS. You don't have to outrun the bear; just the other guy.
Survival? No. Other tanking classes have just as many survival options, if not more/better (looking at you, Mr I-rez-myself-free-every-two-minutes-adin)