regular email digests
trust levels for users
var. spam detection methods
similar topics blocks
categories with category description and category icon
I know it is blasphemy to reply/reopen an old thread, but I think I have some sort of workaround for this. Say that per-category header warning message is 1) not going to be as native functionality, or 2) still waiting for plugin for that, I think a pinned thread atop all threads would suffice.