The touch-enabled part of this preview and the fact that Microsoft stays close to their excellent Metro UI looks very promising. I also see the point of keeping the traditional windows elements like the desktop or explorer. However I really don't get why the explorer has to stay that traditional. I'm sure there would have been a way to make it usable with mouse AND touch input - maybe by replacing all those ribbon elements by only the most commonly used actions as icon only, preferably in Metro style.

Right now this feels like an unnecessary break from the promising and fresh approach that is Metro on a desktop (or tablet).