I have some ideas on how gnome could be improved. I'm definitely planning on implementing some of these, and would appreciate your input on this.
- Controls on the panel applets can be implemented as either dlls or as applications that communicate with the panel over dbus - the main reasons for the dll way is that the control can save a few processing cycles and be a little lighter.
- Let controls choose to take care of their own clipping, which makes things like the vista start button and a lot more complex controls possible.
- One specific problem that I have currently is that a lot of time files are saved on the desktop and I have to clean up the desktop regularly. I'm sure others have the same problem, but I also doubt that everyone has it, so maybe this should be something a user can turn off if they don't like it. Maybe we shouldn't allow to save files on the desktop? Only allow objects to be placed directly on it. By objects i mean things like the windows 'my computer' object and the trash bin and maybe also the widgets which seems to be the trend nowadays. So what should happen if a user decides to drag a file on the desktop? If she drags it from the internet the file could be saved in some folder like 'my files' (i beleive os x already has something similar) and notify the user through something like libnotify. If the file is from somewhere on the filesystem perhaps a dialog should appear if the user wants to create a shortcut to that file. What would be even better is if the folder to place the file in could be determined by looking at the file's metadata, which could be anything from the mimetype to the file's author and it's length if this is a video. That would allow for some really cool sorting of files.

- This one is for nautilus and maybe for the open/save file dialog. Currently the previews for the music files start to play a few seconds after the mouse arrow moves over the file, it's annoying when you didn't really want to listen to that file but were looking for something or just moved the mouse accidentally, or maybe the mouse arrow was already over the audio when gnome started (put an audio file in the center of your desktop, and restart X, that should do it). A better way might be to have a button show in the corner of the file icon, that would allow one to play the file when it's pressed. This is similar to KDE 4.0, I beleive.

- This might not belong in gnome, but rather maybe in x.org list: it would be nice if it was possible for the background to gradually change to another one.  OS X already does it, and this seems like a nice feature.