Microsoft should have left the desktop alone
I can understand why Microsoft would alter Windows (proper) in order to give it's new touch-centric platform a push. It's a great strategy but only if you dont mess with the core product too drastically and this is where Microsoft went wrong with Windows 8 for the desktop. But it doesn't have to be that way.
First, they should admit ARM was a waste of time and cut their losses. They were too late. Plain and simple. Intels chip are good enough, no bid deal. Next, they should get rid of Metro when mouse and keyboard are present. Yes, we'll have 2 different environments in one device but at least there'll be a "wall" between the environments. Less confusion, and easier to use. Windows 8 (tablet edition) still gets to piggyback on Windows proper and the marketing message is simpler.
Come to think of it, the first step would have to be: fire Sinofsky. Now that Sinofsky's gone I suspect Microsoft will be going back on some of their more controversial decisions (e.g. no "off-switch" for metro).