Don't PvP as much as I used to on my Warlock anymore, I have an Arcane Mage with 3k+ SP unbuffed and full Relentless gear that I play for PvP now. But when I did used to do PvP on my Warlock I found my old Destro PvE spec just kaned people with Zero Resi in BG's while playing Affy PvP spec for Arena.
My have only been 3 weeks but I remember those 3 weeks when in 3v3 me and a few mates decided to just muck around and take a full Warlock Grp. Urm, that was fun, 1600 Rating (Ok I know its poor compared to what most people are seeing) Demo, Destro and Affy Warlock was pure mental fun. Affy would just CC two of em with Destro's Succy while Demo and Destro burned the healer. Rogues were our only problem.