I think a good first step would be figuring out a way to apply survival mode effects to NPC's. If they have to eat, drink and sleep to not die, they will naturally have to set up a work/eat/sleep schedule- make them want to eat when hungry, drink when thirsty, sleep when tired. Being able to set timeframes for these three activities through a terminal would emulate Rimworld at it's core. After that you can add personalities- weighting likelihood of actions and responses, even dialogue (one liners). Set up booze/entertainment needs and make entertainment more interactive (there is already an abundance of stock furniture with animation cycles), make tamed animals (already there) useful, by allowing settlers to "harvest" ingredients, adding breeding would be a huge plus. Love the idea, would definitely play.
