Since I took over as moderator of Post Processing Forum, I've been encouraging artistic use of processing. There are many topics now that are "how I did this" (layers, textures, filters, special effects, composite work) or simply sharing creative pp work. I encourage those of you who haven't been there for awhile (if ever) to visit!
As for a new section called "Artistic," there already is the Exploration of Digital Artistry section, an invitation-only forum created by Bob Yankle, though that has had very little traffic for a long time. Cwilson co-moderates. Maybe she can weigh in.
The main obstacle for any volunteer-moderated section is its invisibility. While new users to UHH are automatically subscribed to main discussion, Gallery, and a couple of others, in order to see a volunteer-moderated section (there are over 25 now, I think!) in "newest topics," you must subscribe.
Additionally, for those who rely on the Daily Digest, even when you're subscribed to specialty sections, they won't show up in the digest 'til you've logged into UHH.
Close-Up Forum may be the most active of the long-established volunteer-moderated sections. I've been trying to bring PP Forum from fewer than 20 topics per
month in 2018 to an average of about 3 or 4 per day. This requires constant "advertising" and recruitment
To compare traffic, main discussion can see 20 topics in a single day and Gallery has upwards of 50!
One last thought: even when someone is subscribed to a specialty section, they may decide that only receiving 2 or 3 comments on a topic is not worth their posting. Supporting a small community is not of interest to many UHH users.
I'll be interested to hear other viewpoints!