Well, to keep this in perspective for you, I had my warlocks at level 66 and a friend was just starting a DK. My warlocks were specced demonology at the time (the felguards were tanking instances), he was specced unholy.

I took him through ramparts when he hit level 60 and he outdps'ed all of my guys who were 6 levels higher than him.

Class balance, heh.