Most of these conversations are not happening at all. Since
maintainers don't approach designers, I think we need to do this the
other way around:
Designers should find apps which require design attention, and file
bugs about UX problems in them and submit mockups.

Some apps which I think could use some design attention:
 * firewall-config
 * selinux troubleshooter
 * gnome-abrt (in this case the maintainer is already listening to
design feedback and implementing fixes, which is great, but more
design input would be useful)
 * DevAssistant
 *

I'm aware that in the past work was being done at least on some of
these apps, but they have a lot of UX problems which should be
addressed in my opinion - and I'm not saying designers who work /
worked on these apps do / did a bad job, I'm just saying there's more
to be done.

And I'm sure there are a lot more apps in Fedora which could use
design attention.