Unlike most of the wrath-babies here... I started my lock toward the end of vanilla, and leveled her very slowly and casually through mid-bc. Began raiding mid-bc and raided through end-bc.
I loved the way my lock played back in vanilla/bc. The dots actually did something without having to babysit them. You didn't have to pretend to be a mage. You did your questing and killing by sucking the life force from your foes. You were evil and vampiric, and the playstyle was fun and uniqe.
Then a bunch of whiners who were used to locks being free HKs in pvp banded together and spammed the forums. Granted in the beginning our dots WERE too powerful, but by the end of the xpac they were in line. Still, this wasn't enough for these whiny little (explative deleted)s. In pvp most melee classes had more than enough back then to paste a warlock, and a good healer knew how to dispel and counter them, but bads continued to shry and scream, even though by then warriors were by FAR more overpowered than locks ever were, and when all was said and done we got our dots cut in half, freaking haunt, and our drains cut to 1/4.
Frankly, I'd rather have had UA's explosion removed so our dots would separate good players who knew where the dispel key was from terribads than have the dots and drains that made the class what it was GUTTED.
I have to say haunt was the worst thing to happen to the spec. Blizzard took a smooth, synergistic toolkit of dots and regen mechanics, destroyed them, and lumped most of their utility into a cooldown, hard-casted spell.
Worst of all, the spell did not last long enough to actually boost all your dots until months after wrath's launch! So when I tried a dummy after 3.0 dropped, and spent 3 hours afterward untangling my fingers (4 more dots to refresh back then), then tried to aoe farm like I used to and ended up a smudge on the rock, I decided i'd take the LESS stressful role of healing during wrath. (as a holy priest I utterly embarrassed resto druids that whole xpac)
Every major patch and expansion I had hoped I'd see a return to what warlocks actually should be, but every patch they continue to make them more and more of a mage wanna-be.
Ramp-up was already a slight issue during BC, but in LK we saw it become a concern, and now in cataclysm it's outright catastrophic.
While the mage gets off 2 fireballs and a hot-streak pyroblast (which, btw, hits as hard as soul fire CRITS AND PROCS 20X AS OFTEN), destruction is still just "setting up".
In the beta, affliction is now hobbled not only by haunt, but MG. It has gone from the most mobile and unique class in pve to the most stationary and fragile, having to cast bolts AND stand and channel. I think it's the ultimate insult that spriests have more powerful baseline dots than affliction.
To me the archetype of the warlock will always be one that scoffs at the concept of mage escapes, that dots 4 mobs and laughs while sucking the life from them. That uses siphon and drain life as active mitigation in pvp. Until I see warlocks back along this malefic path I'll consider them a lost class.