The Melee are actually performing quite admirably. There may be some issues when the DK gets up and running and reworking how positioning works, especially on large bosses (dragons in particular come to mind), but hands down their best quality is the fact the keep whacking away with their constantly refilling fuel supply, and fears don't mess them up nearly as bad as casters. My 3-man of Attumen worked largely in part due to the fact that my Warrior just kept whacking and building rage while my Shaman and Paladin (who was tanking) took turns healing the tank.

Edit: and because I came home to down servers, I'll elaborate. Casters win hands down on front loaded damage, They start a fight with a full bar of mana bar, typically with cool downs to blow. Rogues and Warriors and Deathknights have to work up their combo points and poison and rage and shouts and runic power, but once they get going they don't have to stop to evocate or life tap or slow down becuase they went OOM at 5% left on the boss. Similarly, out and about in day to day activity, the guys who get that first hit in are going to naturally pull ahead on whatever damage counter is used.