I have been playing the alpha on my Surface Pro 2. Graphics wise I didn't have many issues. It ran at 1080p fullscreen smoothly, though I think I did turn down the Anti-aliasing (which by default was 4x). Turn based games in general tend to work very well with touch interfaces.
Most of the general game play works very well with touch, i mean of course if you are trying to order a ship to move and you are zoomed out all the way... you don't really expect it to be right on the mark...
The biggest problems I faced were actually the resource allocation pallet, and other elements of the UI (buttons/menu) that are tucked around the edges of the display area which make it really difficult to activate. (and they are small..... )
It is pleasant to play, but I will admit that I need to use either the pen, or I need to zoom in to get the detail movement. Could be improved, and I would deeply enjoy the opportunity to assist with this optimization.
(Shameless self plug. I was a guest of Microsoft's at the Pro 2 launch, and wrote a couple of articles about gaming with Surface Pro in addition to talking to most of the press there. Most of the video out there that shows Portal 2 being played at that event is me.) http://1drv.ms/1sZmb89