Personally, I think MS needs to stop "innovating" with WPF and wait for developers to catch up. Does anyone feel overwhelmed by all of the new frameworks being thrown out of Redmond? WPF, WF, MVC, EF, LINQ, SL, ... It seems like I've barely gotten comfortable with one when there are two replacements for it.
Nonsense. These are not replacements, these are complementary. But yes, it's overwhelming at times.
At least it doesn't make any sense to stop progress because we can't keep up with everything.