Visual Studio 2012 often crashes, the API documentation is often incomplete and not helpful, there are quite a number of incompatibilities between W8 and WP8, XAML has mediocre performance on ARM and can't be accessed from C++ on WP8, the list goes on and on.
If anything, Microsoft managed to make most Windows developers I know want to work on linux/Android or OSX/iOS instead - the rest are blissfully unaware of what UNIX is in the first place.
Sure these things may improve over time, but right now developers are nothing more than beta testers. For us, the possible profits are not worth the efforts to deal with the mediocre development experience.