Melee is tough to deal with period, yet people still play rogues (which can be even harder IMO then warriors). If you can deal with positioning issues I think a DK team would be pretty bad ass. Nothing says you can't try it and see how you like it.

If nothing else I would recommend EVERYONE to play a DK through at least their starting area quests, that is the best quest chain in the game period, hands down, it is awesome.