Hi Ad!
First, let me say that you were a visionary 2-3 years ago when you started to propose Discourse as a complement/alternative to our mailing lists. The rest of us are starting to catch up. :)
I actually learned only yesterday about this list, because we need a Mailman list to test -- see for instance https://discourse-mediawiki.wmflabs.org/t/problems-with-email-forwarded-to-a...
In order to test better, could you grant me admin rights? For instance, we have a problem with emails forwarded to lists, and Tgr wonders whether this list is configured to distribute text-only messages or MIME is fine too. I would like to play and test with the different settings of the list.