There's nothing inherintly bad about Win32, it's all the legacy apps that are poorly suited for a WOA device that they want to exclude. The apps make the device, and if certain companies can get away with recompiling the same old crap, then it's bad for the users and therefore bad for Windows.
Find me a company that has a product on more than one platform and who doesn't just shunt their crappy application on top of an abstraction that allows it to sit on both platforms.
You think World of Warcraft has a different source code base for Mac, despite being unable to use Win32? You think Photoshop does?
At least keeping Win32 around means that applications can be as inefficient as they were, without forcing them to abstract their crappy apps and make them more inefficient.