Interesting poll!
Didn't play Warlock enough in TBC & Wrath to have much of an opinion on them. I played Affliction, and I enjoyed it, enough so that when I rerolled late Wrath I made Warlock my new main, but I had little time to play it at max level before Cata changes came. Cata was allright, played all 3 specs, prefered Affli still. Mists was great I feel. Love the new Affliction, and have grown fond of Destro how it currently is. I like Demo much better these days too, compared to the clunkiness of Mastery snapshotting in Cata.
To be honest though, I always kinda prefer the new versions of things. I like change to a degree, so if you ask me this question in the next expansion I'll probably prefer the way the specs play then, compared to now.