There's other options. I've recently started a 2v2 team with my destro lock and a friend's dsic priest. I basically open up by setting the felhound onto a spell user to silence them early then open up on the other character with an immolate, chaos bold then conflagerate. If you had 4 felhounds, that would be a lot of spell interupts. I can only guess how fun it would be to see 4 chaos bolts insta-gib someone!

I think that all warlock secs bring something. 4x CoA and corruption would cause a lot of havoc, especially if you got it off on everyone.....lots of dispelling involved to get rid of that...giving you more opportunity to incinerate or shadowbolt.

If you're levelling in BGs then you'll have plenty of time to work on it. I'm actually levelling a second lock to dual box in arena