Somehow natural mob spawning is broken, just stop needing the natural spawn rate and just allow the natural spawn rate for a hard world. If you want less mob spawns just change the difficulty to normal. It isn't right that we don't have mob spawns just because the server wants lowered rates and it isn't fixed atm.
I also hope this won't be a suggestion that if accepted sits on trello for even a month since this isn't a very hard fix and is crucial to any survival based world.
