I played a little JA2 on my wife's Surface Pro; it seemed perfectly fine via touch.

I've seen my friend playing Heroes of Might and Magic 3 on his Windows 8 tablet. Worked pretty well :)

I played Ultima VII with Exult on an old HTC Windows Mobile phone, I think it was an HTC Touch, it was somewhat slow but I was able to move the Avatar around and all. I think nowadays you have a port of Exult for everything including the PSP :D.