This guy gets why MS made the right decisions with windows 8...

What if Microsoft had kept tablet support separate from desktop Windows? That is, what if Microsoft had three different versions of Windows (Windows Phone, Windows Tablet, and Windows Desktop) with a common underpinning (NT) but separate user experiences. Windows Tablet would have been the full-on “Metro” experience, including finishing the job of completely eliminating the Desktop. Windows Desktop would have been more of a 7.5 product, combining the underlying architectural improvements in Windows 8 (faster boot, Secure Boot, better multi-monitor support, SmartScreen, etc.) with minor tweaks to the Windows 7 desktop UI experience and Win32. What Windows Desktop would NOT include is the Start Screen, Contracts, or the ability to run Windows Store apps. Why not? Well, the claim is that desktop users hate those so why not keep the environment clean? (And if did include them, then it would just be Windows 8 as we know it!)What would have happened in this scenario? Well we know what would have happened to Windows Tablet because Windows RT is Windows Tablet V1.0. Windows RT is struggling due to the relative paucity of Windows Store apps. The main criticism of Windows RT is that it can’t run desktop apps. But the ability to run desktop apps is exactly what gives you the “jarring” and unnatural experience that people complain about. So analyzing the first few months of Windows RT suggests that a pure tablet OS from Microsoft would have failed.
http://hal2020.com/2013/03/07/what-if-microsoft-had-done-windows-8-differently/