Well David does art and a large chunk of the story, and I remember seeing somewhere that most of the writing is done (maybe I just imagined it). So that part shouldn't impact Alex too much, but the question is how time consuming will be all the polish of the new content, as will bug hunting and fixing. The only way we can be sure what we both said is true, is if we don't get any more development blog posts. And IF there's something more then it'll be truly one hell of a wait.
From the looks of things, even Tart may have missed his February prediction. I mean we're probably going to get another set of patch notes before the final push when most of the playtesting will be done, so that's another month give or take.