1.) Metro and the start are now one. Although I did not mind the two modes, integrating into one is nice
2.) Snapping metro tile on the desktop. In 8.1 you can buy an app that does this.. now you can.
3.) Virtual desktops, you can create different desktop themes. I haven't tried it, but I can imagine have a desk top for work application, a gaming desk top, then switch over to a social media theme desk top.
4.) Microsoft announced 10 is free for Windows 7,8 and 8.1 users
That's interesting. And I've heard that. My problem is that the Desktop/Metro separation is the feature I like BEST about 8.1.
It allows for a very clean desktop and the Metro tile based App selection is wonderful. You remember things by position instead of Alphabetical or Most Used at the Top. I like it and would not want to give it up. So if 10.0 does away with that feature I'm going to stick with 8.1.
The reason I like a clean desktop is that I use it too focus on my current projects. I put the folders and shortcuts on the desktop and then remove them when I'm done. Very handy. Back in my Vista Days I had to put 50 shortcuts on the desktop. Not good. The 8.1 scheme is better.