Gamerules /spawnrate and /spawncap

Two gamerules. One adjusting the amount that mobs spawn (example: mobs spawn twice as much, three times as much, etc) and the other that adjust the amount of mobs that can be rendered at one time (example: 50, 100, 150, etc). This would make for some really good challenges, for example "Can I beat Minecraft with 100x the mobs?"