I think one reason the Packaging and PEPs topics are popular here is that there may have been inadequate previous communications infrastructure for having conversations about those topics. So perhaps there are other such topics, underserved by their current mailing lists and so on, that would be useful to invite and to seed with starter conversations here?
Also, more folks of more diverse interests would come here if we linked to this Discourse instance more systematically, such as in the Python developers’ guide and on the Community page of www.python.org. (I’ve just done a tiny bit of this; the Forums page now links to this Discourse.) Perhaps people interested in directing more folks here could write occasional “recent threads on Discourse you should check out” mailing list posts to comp.lang.python and similar lists, or blog posts that get syndicated to the Planet.