Compiz is dead.
Metacity is going to die. Canonical has to find a replacement WM for Unity or shove up the development of compiz to someone else. Wayland may replace X11 (and I hope it will be good once it do.) Shit happens as usual. (Even good shit.)
I'm thinking about abandoning Metacity support for my themes too. My next theme that I've started working on is not going to have a Metacity theme as I see no point in supporting it when I'm not using it and when it's going to be abandoned. A quote from the musical artist Pogo:
"I don't make art for you, I make art for myself."
In the end I just get tired of trying to fix things for stuff that I'm not using. One reason why I scrapped Zukitwo-Dark. May not be a great excuse, but lack of standards makes certain things annoying to deal with. But sometimes I also want to fix bugs for things that I don't use, because it feels better to have something that is "complete."
But when I think about all this fragmentation I also think about Elementary OS Luna that seems to do things right, especially with application design. I'm not saying that eOS Luna is perfect. Personally there are a few things about their interface that I just find a little bit annoying. Example: Docks may look nice but tend to grow annoying. I believe a desktop can work with 1 bar or panel. 1 click (mostly), 1 panel, 1 everything and always accessible are my thoughts right now.
And some thoughts about that Cinnamon desktop. It feels very amateurish as of right now. I have to configure it for over an hour to make it look the way I want, and even then it's not perfect. Gnome 3.8 may bring a "fallback" desktop that may be similar to the old Gnome setup. I wonder if that will do it better than Cinnamon.
We'll see what comes next. In 10 years we may need to create interfaces for holographic displays.