This new "feature" is absolutely absurd. Not only does the "window menu" drop-down on mouse hover---which is bad enough when using any app that has navigation/UI elements at the top of the screen---but also when switching between apps. So if I switch from the desktop or some other app to Chrome in the Modern UI, I have to wait until the thoroughly useless thing disappears before I can switch tabs using the mouse.
I was in the small minority of users who actually preferred the Modern interface to the conventional Win X desktop. It reminded me a lot of using tiling window managers like Stumpwm and Ratpoison in Linux---window managers I vastly preferred to explorer or whatever it was called. But now? This is a huge regression, and a complete turn-off; all the more so because you can't actually turn it off!