Celestalon started the talk about what abilities would we be sad over losing. I don't know that warlocks would lose many spells with our recent expansion overhaul -- we're pretty streamlined as it is. Veteran warlocks can see and feel the difference between Cataclysm's complication and Mists' minimalism every time they play.
A warlock class strength is that we're so flexible at dealing damage, whether we do it through DoTs or with direct damage, or whether we're single target masters or AoE beasts. So we end up with a good deal of situational abilities that confuse the casual or fresh warlock as to what should be keybound. We might not lose the amount of abilities that, say, hunters will, but we're likely not immune from the chopping block. Let's talk some suggestions.