xscreensaver has been in fedora-core for a long time, is well integrated into
the Linux desktop environment, serves us well, is well maintained, and has the
rarely seen combination of a nice simple user interface and functionality
superior to any alternatives.
I don't see any reason for including gnome-screensaver in fedora-core - it beats
xscreensaver on none of the above, and falls short on several. So as far as I
can see, the best thing to do would be to move gnome-screensaver to extras.
Google fedora gnome-screensaver for discussions about this. If nothing found,
propose it to fedora-devel list. Then, if approved by developers, re-open the
bug and post the link to the thread.
AFAIK it will replace xscreensaver in future.