Just so we have a record of things that need being done :)

-Nether wart and warped wart replanting by mobs
-Glowstone regrowing like coral
-Skeleton structure spawning under a ghast dying
-Soul soil turning to soul sand when a mob dies on it
-Could Piglins slowly rebuild a bastion?

I really like the bastion idea, they could possibly also interact with the chests? Refilling them with gold and nether resources?
Actually could villagers do this too?

This will likely be the centerpiece of the next release. It's likely to happen.