This is why Xfce was dropped from Fedora Core 4

[Thetargos]

I just want to add something to this discussion... Fedora indeed
droped XFCE from CORE (i.e the next CD release), however XFCE will
STILL be available from FEDORA EXTRAS, a new repository with lots and
lots of software that for any number of reasons are not included in
CORE, BUT still supported by the distribution. The discussion abou
this issue in the Feodra Lists was that there were a number of
unmaintained packages (apparently some inside Fedora as well), and as
such XFCE was dropped from CORE into EXTRAS. Maybe the new EXTRAS
maintainers will do such a good job that XFCE may make it again into
CORE by FC5, nothing's  for sure, however Fedora users (like me) will
still be able to run this incredibly well done DE from the official
EXTRAS repo.