There is a perfectly good GUI for that setting, as with all the GConf settings, on my Fedora
system it's Applications -> System Tools -> Configuration editor. It includes search* so that
you can quickly find settings you want. You are of course also welcome to write a GUI
configuration tool that has exactly the fourteen settings you think should be configurable,
without also listing the hundreds of other settings you think only idiots would change, but
since everyone's list is different your tool may have a limited audience...
* although in this case you'll find a bug, searching for "cursor" doesn't match the relevant
configuration setting even though it obviously should. Some other entries about cursors are
found instead, someone more patient than me could investigate whether this is fixed in a newer
GNOME than my 2.20.3
Also, you DO right click on the desktop and bring up a context menu item to change the
background in GNOME. But what are you clicking on? When Nautilus is running (which is the
default for GNOME users) then the background is owned by Nautilus. Since our Grumpy Editor
wasn't running Nautilus there was nothing to click on except the empty root window.