Microsoft is making Windows 8 painful for non-tablet users, but CAD is a natural for tablets. So, which CAD vendor will be first? There are a few tablet-ready contenders:
MoI (moment of inspiration) was designed from the ground up for tablet use. It got bought by Alibre, which was then swallowed up by 3D Systems. See moi3d.com
AutoCAD got a pair of system variables last year that hint at tablet interactivity. Nothing seems to be happening with them, even in this week's release of AutoCAD 2013.
SpaceClaim last year also was boasting of it designed-for-touch-screens features. This year, not so much.
If they get their software working with Metro UI (designed for cell phones, not computers), here are the touch actions Microsoft will expect them to implement: