MSFT is launching Windows 8 with an oldschool pay to play for an OS mentality. Unfortunately they have a huge uphill battle against iOS and Android. For them to gain any traction quickly in this field they will need to expand the devices that Windows 8 can be installed on to any Android Device with an unlocked bootloader.
This would instantly give Windows 8 a huge boost and also get many Developers involved which is really a key demographic to win if they are to have success with Windows 8 on ARM.
I would suggest to MSFT that Windows 8 on ARM be free, and free to run on any unlocked device. MSFT may realize other revenue streams including charging OEMs for support. Charge for a good x86 to ARM emulator, charge for Office etc. AND take donations. I know its not how company's ran in the past but this new world people support devs and technicians directly, MSFT may have some luck getting some donations. Make money off an integrated (vertical please) App (only) store, but perhaps don't track your users, let them know they aren't being tracked, it will buy MSFT some great publicity and highlight an issue with your competitors. Or perhaps a paid version with no tracking and a free version with Android like tracking.
If they do this right they should capture the interests of developers who will make great apps and start off with a much larger user base then if they proceed with this ludicrous UEFI Mandate (MSFT you may not sell as many Win8 on ARM devices as you project, have you seen how dedicated iOS and Android users are?)
Don't get me wrong, I am really excited by Win 8 but lets be honest I don't think Win 7 Mobile and Win 7.5 have put up "game changing" numbers. If done right the integrated nature of Win 8 may make the world more productive.