I think it would be good to add the ability for players to add and remove permissions for their claims. Like enabling/disabling mob spawning. It would help so multiple different claims arent required in different worlds just so you can use "hostile" mob spawners.
Could you elaborate on the idea. You want the overworld to have enabled hostile Mob spawning and have claims disable them from spawning in claims?
I think they mean to have the ability to toggle them on/off within their claims, but not have them spawning in non-claim areas at all. that way players who wanted to use hostile mob spawners could use them in the overworld without issue, but be able to turn it off if they removed the spawners, or changed their location, etc, but players who don't want hostile mobs at all would be completely unfettered.