I was thinking it might be nice if xorg-x11 was in the scope of system packages. I think that very few people concern themselves with the dependencies of xorg, as changes aren't really tangible to the end user. I use emerge -uD system when I want a system up to date, but don't waste energy on packages I barely use. I regard updating the xorg-x11 meta package the same way.
(Please note I wouldn't bring this up if I didn't think it relative simple to implement.)
Many people haven't X11 on their systems. May be you should add xorg-x11 to system independently?
No way. The system set defines a minimal set of packages which are needed to get a linux system booted and working.
Consider a user setting up a gentoo-server being forced to install xorg-x11 just because it's in the system set.
This kind of changes will never happen.
Ok, I guess I didn't understand how the system set worked.