Simplest tank class to play (including DKs in WOTLK)

[Griznah]

Pala is better for tanking because of reactive threatbuilding (as in, getting hit = generating threat).
But all will be viable in Wotlk.
Remember tho, thundeclap will have a CD, swipe won't. DK will have Death'n'Decay, it's almost like concencrate.