I can't say I'm cheering for the new developer platforms MS is pooping out this time around. I've got experience with WPF, and it is a horribly over-engineered piece of bloat. It can do some nice things, but even .NET v4 on Windows 7 has so many basic issues
that doing what you want with it is never an actual option. I cannot count the amount of bugs I have worked around so far, assuming I was able to do so. My other grudges is that it, and every new OS version, just mess up accepted interface guidelines so designers can invent their own wonderous new thingy majiggies on top of existing controls. Even when I do my best to have the controls mimic the Windows ones, it looks fake and behaves subtly different. What is the point of having visual styles and themes anymore?
Win32 is not at all a pretty API, and yes, it shows its age and can use some improvements. However, it is FULL of fixed bugs, stability and is the most efficient thing there will ever be for application development. They need to stop trying to throw it away, since they've already shown that the .NET framework, and WPF in particular, have more holes, bugs and regressions compared to Win32 in it than they can fix in the next 10 years.