I don't agree that the later KDE and Gnome releases where steps backwards, in fact I think they've made solid progress towards matching OSX and Windows in terms of ease-of-use. On the other hand, this could be exactly the problem. It does seem that the more the Linux environments pursue the same goals as OSX and Windows, the stronger the backlash.
Windows 8 was a huge step backwards in usability. I had to use it for a couple of weeks before I figured out how to get Linux on a new laptop secure boot. I am using XFCE these days, because it behaves the way I am used to. No need to learn a whole new set of gestures or click combinations to do what I already know.
Windows 8 is a huge step forward in my opinion. It's faster and more stable than 7, the touch drivers work great (I use desktop apps all the time on my Surface Pro and Dell Venue Pro 8) and it's paved the way for running Windows on non-Intel chips as well as for converging the desktop and mobile which is something that I want.
Right now I don't care about the Metro interface at all - 99% of the time, I only see it when I use the Start screen, which is fantastic and works much, much better than the old Start menu despite the loss of recent-document jump lists per app. But, I can see a huge potential in Metro.
KDE 1-3 and Gnome 1 were a good desktop environment. I don't get why some devs prefer to rewrite good things. KDE 4 and Gnome 3 hurt the Linux desktop and users are searching for alternatives (http://en.wikipedia.org/wiki/KDE_4#Reception , http://en.wikipedia.org/wiki/GNOME_2#GNOME_3 )