I have controversial thoughts about this. As many others I also used to think that it is Ballmer who should have left the company years ago. But now I am unsure. Some of the mistakes MSFT did in the past years might be caused by Sinofsky's presence. I believe that the Windows department had a huge impact in killing Silverlight. And although I didn't jump the SL bandwagon, this was the rudest thing MS did with their developers in the last decade.
Maybe, maybe things going to get better now?