Lawl, Warlocks is easy to beat if you do the right thing.
Okay, they have dots. Who cares.
Mages a defiantely best at BGs when fighting warlocks.
Spellsteal shield, use Mana shield and then you are already more challenging from there.
But if your frost spec, you can also just do Ice Barrier, which makes everything double as better.
Frost Nova the annoying felhunter, and thats it.

You have no counter for Fear or HoT in there. Also god help you if you use anything other than instant casts against a warlock with a Felhunter out. DoTs are going to get to you unless you can kill the lock before its over and even then in a BG it won't matter. Then the lock also has curses. You're strat really only works if the lock is crappy, which is probably the case in BGs.