They are totally revamping the Warlock mechanics in Cataclysm. The details are limited and because we are talking a year out, subject to change.
I will master the warlock in what ever form Blizzard gives to me.
Here are the slides that pertained to the warlock. You can see here some slides from other parts of the panel, like hunters, raids, new race overview, and there is an actual picture of Ghostcrawler. (Sorry for fuzzy or duplicate pictures.)