Speaking from experience, three warlocks would be extremely fast. Particularly as you get higher level.

However, to make things quicker, you might want to add a healing class in there. Wouldn't need to be healing spec while levelling, a shadow priest for example could through a few heals or rez if needed.

2 locks and a mage could also be good. If you got the aoe targetting down well, it could be carnage with rain of fire x2 and blizzard. Would mean free food/drink and teleports too. No wipe recovery though.



It really all depends on what you want to do with them. What is your end goal?