I think Windows 8 could be improved considerably for mouse users if they made the mousewheel scroll inertially. I have a mouse that physically spins inertially, which helps, but it would be nice if a quick rotation of the mousewheel behaved analogously to kinetic scrolling with a flick gesture with your finger. The issue then would be how to make the scrolling stop. I think a left mouse click, which is analagous to a simple finger touch to stop kinetic scrolling, would make sense as the action to stop an inertial scroll with a mousewheel.
There has to be some software patent holder preventing them from doing this. When using the mouse, the metro environment feels like anything but fluid. And then there is the issue of orientation. Mouse wheels are orientated vertically, while everything in metro is horizontal.
After that, you have the dead space. The white space areas of your app. You should be able to drag that space around with the mouse as you can with touch. I don't know the design reasons behind this, but I would think it has to do more with legal than engineering issues.