Feature description
An configuration which allows for disabling certain worlds where using /marry sethome wouldn't be allowed, or a permission for allowing disallowing the usage of /marry sethome (which would be just as usefull since permissions can be negated per world)

How the feature is useful
It would allow for me to stop users from setting homes in an rpg world where I just don't want them to spawn inside hard to access areas.

There already are permissions for that.
marry.home controls if a player can teleport to a home
marry.sethome controls if a player can set a home
marry.delhome controls if a player can delete a home
marry.home.* combines the previous 3 in one permission

You should be able to give fine control over what is allowed in which world through your permission plugin.

Ah ok. I checked the bukkit permission list which is probably outdated.