Good question. It is still beta and the bugs you find with some of the patches are a stark reminder of this. They patched the game three times in the last patch, with one of the bugs being Windrunner and some other heroes resulted in a game disconnect and abandon if you chose to play them. Anyway, I believe I read somewhere that the developers were trying to "speed up" the final release, so I guess it will be done "soon". I think there is evidence of this in the sheer number of Dota 2 invites that have been going out lately. It's not uncommon to receive like 13 x keys at once, and I think they wouldn't be giving out so many invites if they didn't think the game/network could handle the extra influx of players.