Locks are crazy fun. I had a 60 solo lock in ok gear when TBC hit. She hit 70 a full day faster then my main VERY well (at the time) geared warrior. She could just run around dotting 5-6 mobs at a time up to her level, do it 3-4 time and then drink.

I keep a succy out with no abilities turned on and used her as a mana battery that can DPS and out live an imp if she gets aggro.

On my 3x lock 1x priest team I keep 1 imp and two succys out. Imp DPSs for now but when Dark Pact hits fireball gets turned off. Even now it is pretty much nonstop killing. They are not RAF enabled but will get a 4th lock added from the gift levels.