What looks like a marginal jump from windows 7 UX to windows 8 UX, might be a little too much of a change for XP and older users. It will be interesting to see if this gets tweaked in the future releases.
Totally. The shift for XP users is really really big.
XP is a decade old. Those users are going to have to buck up. Besides, it's not like they could switch to anything else that would be less jarring than Windows 8.