Haha, focus.
Just installed Raring again last night and noticed the long-standing bug (compiz and gnome-terminal where the window won't keep its size if not on the first tab) still in the newest release. How about broken window resizing, where you only get an outline like in Windows 3.1? I could go on, and on, and on.
Meanwhile they have people writing display servers and a new mobile interface for xsake.
I'd kill for a modern, mature workstation OS in the tradition of NextStep, or SGI 4dwm, Windows 2000, even Ubuntu 10.04, etc. I like lots of the other choices, say Cinammon, XCFE, etc, but they are unfinished or not integrated well. Gnome has destroyed many of the powerful tools these products share. KDE has nice tech but is too cluttered. OSX is nice but we use linux everywhere. I'll be trying Mint 15 soon and crossing my fingers.
I know that the linux desktop has been a boondoggle for years but perhaps there is a market for workstation-oriented distribution with deep integration and features that work. Would enough people pay for that? I would. Is it enough for a small startup to get funded? I'd be interested in starting one, though I realize it is unlikely.