If they really intend to get the game shipped in time for the Christmas buying season, they need to get the demo out ASAP, and then they're gonna have to rush the tweaks in response to user input (from the demo) like mad, so that they can get the final game out quickly.
I somehow get the feeling that there have been closed demos released for testing, and that we're likely to see the final game on the shelf at the same time as we get the demo (regardless of what has been said before). I mean, look at all the 'two more weeks' comments. That tells me how trustworthy their estimates of what's going to happen and what needs to happen are..
P.S.- I don't really care if they solicite my input from the demo. I'll be buying the game the minute it hits the shelves, simply based on the leaked 927 and the fact that I know the final can't be worse.