I installed the 32bit dev preview to a VM. I think it will work just fine. You only ever get Metro when the machine first boots or you press the windows key/start button. Then you just type as normal.
I think there's good potential here, Microsoft is looking to build one OS for every device, and they're certainly not saying you have to have a touch screen and use Metro for everything. I already have an iPad, but if I was to get a second tablet I'd probably look towards windows8 before android.
If I can get a good download of the 64bit version that comes with dev tools I'd like to see how easy/hard it will be to develop programs.