1. Some of us have the preposterous notion that the NT kernel is superior and more modern than the BSD kernel.
2. The NT kernel architecture is not new by any means. It's mature and robust.
3. Whats wrong with their windowing system? The DWM is pretty speedy, efficient, and stable.
4. "This would also open Windows for serious software development"?! It's currently the number one consumer (some, including me, might argue iOS actually is), and the number one business and server OS. How much farther ahead of the pack does it need to be before you'd consider it "serious"?