I doubt it'llbe that bad, but it will be a good test of whether tablets are for content consumption (ie iOS- stripped down, restricted, but works) or more serious work (windows- more powerful, but more complicated)
Given that the ARM versions of 8 won't run Windows binaries anyway, I don't really see the point of even having the desktop mode on tablet versions of 8. I was excited about the possibility of Transformer-like Win 8 machines, but unless somebody makes an x86-based tablet/converitble, Windows 8 seems destined to be a tablet OS first.