Completely empty magazines could probably be automatically deleted after a month. Anything with actual posts should probably be reviewed by an actual human, and only deleted manually. Even if there's only one post, it could be a very useful post that shouldn't be deleted. Or maybe the magazine is being used as a "signpost" to direct people elsewhere, like r/traa pointing to r/traaaaaaannnnnnnnnns.

The process of flagging magazines for review could still be automated. Maybe each post made delays the review flag by a week, that way active magazines won't come up. Admins could also "snooze" the flag for a set amount of time, or disable it permanently for some magazines.

Magazines that are abandoned but still have useful content should be actively advertised somewhere as "available for adoption". The same goes for magazines that are reported by users as unmoderated.