Well, trying to make linux more like OSX or win (which is what xfce, KDE and GNOME do) is bounded to fail. I think there are qualities on linux that are both unique and elegant, for example tiling window managers. This is where most research in UX should go. Users of others OSs are not stupid, they long for enhanced productivity. If they see it in say a tiling WM, they may want it, and currently the only way to get it is in linux (more or less).