Personally i think a caster DD is the best, and in my opinion, Wizards are the strongest casters in the game, if built right. Casters damage is almost always consitant where a melees damage is within a range. The only time a caster's damage is incosistant is when somthing has a resistance to the element of the spell, then the caster can just switch off to another element and be fine. Another thing that i have experienced is that a well built wizard will go oom a little less then a well built rogue, this is just cause how i played, might not be same as how someones else builds there wizard. i have a 60 sorcerer who went mana path and his mana is usually really high and because of that he has more PoT thus allowing me to chain cast my spells for a longer period of time.