On raid situations, Warriors are obviosly the tankers of uber mobs, and yes sk's can out taunt them....but you'll notice on a uber none will try it....you designate a warrior to tank a mob...then have an order for after they die or lose defensive...sk's use their taunt for pulling and for moving a mob (if it warps up on a wall or firepot)...thats not to say that sk's cant tank though...on regular mobs in tov a sk can tank quite nicely, if they have the gear....A well equiped sk will end up having more ac than a warrior usually....you'll see on certain guild web pages that their sk's can have 1500-1600+ac unbuffed if they're uber enough...But on ubers....warriors will always tank it because of defensive...40% off a max hit from a mob is a hell of a lot if a mob hits for 1200....A warrior will keep aggro tho on uber mobs with defensive on just b/c he's the only one taunting, and he's usually solo'n the mob for about 5-10 seconds before everyone else engages...
Sk's can taunt better, but its to do a different job most of the time...