I think the fact windows 8 will work on multiple chipsets will be a real asset.
Imagine being able to install full versions, not stripped down ones, on a tablet.
Not going to happen any time in the foreseeable.
What I, and most business and professional users, use the full version of Windows for, can't be done, and will never be done, on a tablet. It's not an appropriate physical vehicle for that kind of work. And that market is Microsoft's core.
OTOH, if all you're talking about is email, web surfing, some powerpoint, light wordprocessing, and tiny spreadsheets, sure, you can squeeze that into a tablet.
Tablets are terrific for lightweight communications and media consumption. And the app market has exploded with thousands of handheld applications that nobody foresaw even 5 years ago when the iPhone came out. But the point it, you don't need full-blown Windows for that.
I do not believe that installing a full version of any real operating system on a tablet will be effective use of the resources. The stripped down version is fine, for what tablets are best at.
That's all IMO, of course. :) YMMV.