This seems like a good idea (providing the COPR), but apparently this (Xfce in EPEL) handled by the Xfce SIG rather than the EPEL SIG. Or perhaps both of the Fedora SIGs at once, but at any rate it's not in CentOS Extras.
Putting the packages in a COPR was how it was handled last year, and it seems that it didn't work out perfectly ? But perhaps with some more awareness and documentation, it could be a better and more stable option.
Xfce got off to a slow start, since EPEL-7 was still in beta when CentOS-7 came out. But I wouldn't say it's in a bad shape now, and it already had a pretty good Xfce 4.10 experience even with the Fedora 18 packages.Most of the remaining problems are the same for all of el5-el6-el7, and it's about the completeness of the packaging (the rpms and the comps). And possibly doing some branches and rebuilds, of the missing packages.
We have something like 90% on EL6, and 10% on EL5. But only 1% (testing) EL7. So it is more interesting to fix the existing releases, and that doesn't need any Xfce rebases. New fancy stuff from Fedora isn't needed at all, more like rebuilds/branches of old stuff that is missing from EPEL. It would be better to use some mechanism like SCL for add-ons, and keep the mainline at the current Xfce releases. The EL "rebases" *always* seem to break stuff.
There was some talk about an "Alternative Desktops" SIG for CentOS last year, but there wasn't enough interest or volunteers to form a group. Then we tried to narrow it down to just a "Xfce Desktop" group, but in the end that came down to "so just use EPEL". But maybe a spin is a nice focal point, then the packaging can continue in EPEL and the CentOS Xfce SIG can just offer a special ISO with the epel-release and @xfce-desktop already added to it.Basically I just want a better Xfce user experience, not join a club. ;-)