These are all good.

Having seen a few subreddits get taken over by tyrannical mods, I’d like to see some kind of active oversight, or meta moderation. Not sure how that could be implemented. Maybe a voting consensus built into the sub / magazine / community.

Activity and the user experience are both important. Variety too. Special Interest Groups are important.

Region focused communities are another area that deserve attention, though they could be served by geographically based instances.