personally i would take 3 priests over 3 warlocks at that bracket, its pre all the pvp pets

your way to squishy at that level, i tried doing it with my locks its fun you still take out every twinked character due to the dots but a 500 crit that some do trust me will take your toons out in 2 hits garanteed

go priests

shields
heals
buffs
aoe fear (which you wont have btw on a lock this level)
chooseing racials well going alliance it would probably be NE now that Starshards is an instant cast dot. its on par with SWP at that level.

3 priests would gear up nicely too in deadmines and wailing caverns with all the updated blues im sure you could find someone to help rush thru your toons.

http://www.wowhead.com/?talent=bV0hZb

dont bother with shadow spec you dont have enough shadow skills to make it worth your while, and a wand does crazy dps.