I think it would end up exactly like the last time they tried that with the mobile-oriented Windows 8. Nothing has changed since then that would make an attempt any easier. Windows has far too much legacy cruft and everything's spread across a dozen different GUI toolkits and design languages. They still haven't even managed to completely eliminate Control Panel after 13 years of trying.
>>adithy+d
It's worse even than the "vital apps" ecosystem - who would leave their preferred "walled garden" when so many dials have been set to make that the maximum frustration?