Usablity and functionality go hand in hand as far as a desktop environment is concerned. The more functional the desktop, the more usable it becomes. And the more usable it is , more people start using it. The Gnome developers have given this a great deal of thought and the results are for all to see in the latest versions of Gnome which even a child can navigate. But does that mean we have reached the end of the road as far as desktop usability is concerned? Not at all. There is still scope for improvement. The challenge is in making the desktop as feature rich and functional as possible without overwhelming the user.
Peter Chabada has listed over 40 suggestions which he feels could make the Linux desktop (particularly Gnome) more user friendly. His idea is to keep the Gnome desktop simple but make it wield more power through added features. Perhaps the Gnome developers could incorporate some of these features in the next release of Gnome.