One of the key things that often gets overlooked is WM7's requirement for a capacitive screen. This will make it very difficult to port over to any existing devices (HD2 being the notable exception). Even if someone does figure out how to get it to work, it is likely our beloved TP2's/Tilts, etc. wouldn't have enough horsepower to make it work effectively.
And I am not sure capacitive screens will be "better" - While they may be more finger friendly (I have an iTouch) you give up the precision of the resistive screens. You could never do handwriting recognition on a capacitive screen for example. For website browsing, I like the ability to pull out my stylus and click a hyperlink among several closely stacked links (a menu bar on the left or right) without the need to zoom in so far that you lose visual perspective of the web page.
Just my 2 pennies worth...
