The only problem with this is that, for this to happen (fallowing the Linux
Permissions System Rules), the file they are editing must be in a "neutral"
place like /etc/de_shell_name/configuration.cfg, and then asking for a
password would be natural and not allowed for everyone. But that would create
a simple and unique DE exactly the same for everyone and I don't think that
this is good. But an idea behind that one could be worked with the same
system, just don't know really how.
I haven't thought of working with Cinnamon, Mate or others projects to be
honest. The best I thought was to take Unity2D and change everything that I
think that should be changed, but in those cases I prefer to start from zero
or from something more "accurate" then Unity2D, so maybe a Gnome-Shell (like
Magic Banana proposed) could be a good idea, but isn't there already a big
number of Gnome alternatives based on Gnome3 ? Would that make me depend on
Gnome3 ? That is the real problem.
PS: About KDE I'm really scared about the fact that Qt as been bought... we
don't know what the future deserves us... but I have to be on this situation
of "We just don't know", it is the worst feeling a team of developers that
worked on a project for YEARS could have.