I would doubt the issue with the Desktop since you can adjust the icon size in the Ribbon, that would probably be larger for tablets by default. I don't know for sure though. In 7, that would a be a HUGE pain, but in 8 and the Ribbon, that's fairly resolved.
I think it would be really practical if they adjusted the default object size up on the tablets, but that hasn't been a feature so far of 8 CP or RP. Although, larger elements could be a feature of the new windows 8 desktop theme.
I go back and forth on increasing the object size on the desktop. It does make everything easier to touch, but if you think 8 looks like playschool, try increasing the size of the desktop elements. You'll be in kindergarten on metro, and borrowing your nearsighted mom's windows 95 machine on the desktop.
There is an added downside of increasing the size of desktop elements. This probably wouldn't be an issue on a higher resolution screen, but on a 1366x768 screen, there are a lot of win7 programs (the ones that you need to run on the desktop) that have their default size preset and unalterable. A good example is the minimum size of a program's installer wizard, or your antivirus' action panel. Increasing the DPI makes many of them larger than the screen area, and there's no way to drag them off the viewable area or minimizing them and scroll around, to get a look at the bits that are too big to fit. Those bits almost always include the "Next," "Ok," and "Cancel" buttons. You end up having to go into the properties for that program and change the scaling preset back for just that app. I don't have any trouble with that, but I think it may be a little more complicated than many users would feel comfortable with. I
Having the keyboard and track pad available at all times will obviate the need that many users would otherwise feel to have more touchable elements on the desktop.
As a touch screen user, that's really the beauty of the metro swipe actions -- you can print, go into settings, close the apps, switch apps, search, and open the start "menu" (read: metro) using elements that are big enough to touch and don't crowd the screen while you're not using them.