NOTE: I wrote this article days ago but since then a few of the following wishes have being granted already(!) or they are going to according to the Gnome roadmap.
There was a big discussion about this a few months ago in a gnome mailing list but here is a recap: Nautilus supports script addons that apply certain actions on the selected files or on the currently open folder. It also has a MIME backend and so certain actions only happen to the correct files. However, the problem here is that the Gnome Project makes no real usage of this ability. Instead of shipping with 2-3 important addons (e.g. "Open Terminal Here" or "Bulk Rename" or "Compress It") it has now completely taken out that context submenu if no scripts are installed on the user's scripts folder. So the problem is now even worse than before, as less and less people even get to know that Nautilus has such support for addons. Addons are a lifesaver and a great feature overall, because they extend the file manager's abilities "for free".
The second problem is that third party Gnome developers haven't realized the importance of creating addons and so all we have are a bunch of bash and perl scripts instead of invoking a well formed API for this sort of job and writing something with a GUI front end (e.g. for the Bulk Rename). Applications like File-Roller add their own menu entries on the Nautilus context menu instead of doing it the right way and placing their entries on an addons submenu, keeping the root submenu clean and without changing too much (depending if something is selected or not). BeOS Tracker supports addons with a clean API and PathFinder too, and we have word that Apple will do so as well for Finder.
Nautilus' New Spatial Mode
While it is still beta quality at best, the fact that there's no way to see which folder I'm in at a glance is really bothersome and makes it difficult to be productive with it. Obviously, the usability of the spatial version of Nautilus still needs lots of work and better integration with the non-spatial version. I will wait for 2.6 for a final verdict as to how well this spatial thing can work. On OSX I can't bear to use it over the default Finder.
A New Modern Theme
Gnome needs a new default theme. Most of the time I find myself using the "Default" Gnome theme, which is simple, fast and up to the point, but it also shows its age. KDE's new Plastik theme is truly marvelous. It is also simple (I love simplicity), but it does have a great design behind it (see: it is not hideous like Keramik is). Gnome needs to enter the 21st century and create a new theme and also modify GTK+ to support new features that take theming to the next level. I am not talking about yet another mediocre theme like most on art.gnome.org, but something "wow," something that can draw new users like a magnet and be clean and professional at the same time. First impressions do count and looks too. Unfortunately.
Older Unix and Linux users love viewports and Metacity has taken this ability away. I don't personally use that feature but I know others who do. A gConf key to enable this (or on Metacity's pref panel) might be a good idea as it is a feature that can be useful sometimes, mostly to programmers. Also, I would like to see Metacity have the "use system's font" ability on its pref panel instead of just in the Gconf Editor, plus I find it important to be enabled by default. The current default metacity font is very small to give the user the notion of "header" or a "title". Headers and titles are usually bolder and bigger. Metacity's default isn't.
Another thing I would like to see is the ability to "glue" the windows at the edges of the monitor (like WinAMP does it, really smooth). I don't want the ability to stick windows on other windows, only against the corners of the monitor, because if that's enabled, window movement is very jerky because you get windows stuck all the time among them. Currently you can use the SHIFT key to do all that, but I am only interested in the monitor's corners which in my opinion makes more sense than having non-smooth window movements.
Also, regarding its theming engine I would like to see an easy way to take 1 or 2 or 3 pixels off (diagonally) from a theme's corners. Also, I would like the ability to lock the height of a theme because there are cases where I would want to put on the window manager the 16x16 app icon (like on Windows), but the height of the window can vary from installation to installation (depending on the user's font setting or even because of the default font setting) and then the icon looks squashed and ugly.
I also need a way for Metacity to tell the theme that a window can be resized or not and so the theme would display a dragger widget on the bottom-right of a window or not (not sure if this is implemented).
Session management could do better. Please help out.
The current alpha version of the new File Selector as seen on GTK+ 2.3.0 is pretty bad (even for beta) and brings nothing new to the plate in terms of ideas and usability. I hope Ximian will have this fixed for Gnome 2.6 properly because breaking it again later won't be as easy and I don't want to be stuck with such a file chooser for the next couple of years.
Volume and Showdesktop Icons
Two gripes of mine for any non-Red Hat desktop: using the gnome panel as a single 48pix panel (popular setup for many), results the "Show Desktop" and "Volume" panel plugins to use huge icons. Red Hat has special patches for these and they render as 24x24 and they look good. The default gnome build doesn't support that and so these huge buttons take a helluva amount of space, plus they look weird being so big.