My prediction is that Avalon v1 will be a throw-away: it is not really the foundation on which you will build applications: V2 will likely not be backwards compatible, they will have to re-architect bits of it: which means that people will end up with two frameworks running side-by-side: Avalon V1 and Avalon V2.
Dave Winer also chimes in with regards to the fact that this probably increases the workload for the Avalon team, and could put things into a death march.
When you ask a Microsoft person to say what Longhorn is supposed to do, you get rambly hand-wavy words that mean nothing. A product with a purpose has a two-sentence description that gets everyone so excited they can’t wait. Longhorn isn’t designed to solve anyone’s problems. I think they all know it, but they can’t say it out loud because they’ve all drunk the Kool Aid on this.
Dave gets points for using one of the most popular terms around Gadgetopia World Headquarters to describe getting buy-in on something: “Drinking the Kool-Aid”