Regarding desktop "improvements", to me, that comes down to how enamoured you are of touch-screen interfaces.
If you're planning on using Win8 on a Tablet, or on a desktop touch-screen, then it provides an interface more suitable to that kind of work.
But as for me, I don't want a "smartphone interface" on my desktop, so in that respect, it brings nothing useful to the table.
I did see a list on the Windows Eight forum about claimed improvements, but since those were mostly for touch screen or cloud computing (neither of which I use with my desktop), I didn't bother to save the list.
You could check over at eightforums.com to see what they have.