Initially I would have focused on one os in phone sized hardware with a strong focus on docking at an external screen. This would have failed though because none of the hardware guys would have had the hardware or any incentive to make it possible. So plan two would be, leave Windows 8 as it is today (with the planned future updates still to come of course) because Windows 8 is fine. I would have focused on tablets and docking. When a tablet is docked at your screen(s) then pressing the windows key would switch focus to the tablet with its start screen so that searching is still facilitated but any app that runs gets run on the attached monitor. The app can then be positions on the monitor just as they can today with the same rules for classic programs and modern apps. Basically the start screen would constantly be visible on your docked device and you could use the attached monitors like a regular desktop today. I would kill off Windows RT because at this point in time it is the dumbest thing ever (although probably gave Intel a kick in the bum). I would maintain the compatibility with ARM though for Modern apps so that options are open for the future.