Yeah, a setting in the form of percentage would be nice as well. I think the Gameplay Settings menu would benefit greatly from population control settings. Aliens and Vampires are supposed to be somewhat rare, in concept. If the NPC spawn percentages could be set by the player, it would make for a more enjoyable game. For my own settings, randomly spawned NPCs would look something like... 10% Aliens, 10% Vampires and 5% Merfolk (as they would be the rarest of all for appearing in town, being sea-dwellers and skittish/reclusive, mythologically speaking.) MCCC's Occult Controls at least seem to help fix it after the fact. Basically, you can turn whoever into whatever anytime.