I'd really like to see a mod where you can make rooms for other characters that you can play and switch between classes.
The catch would be that you would need to have sufficient meals to add more characters to your "rooms" and get negative effects when food is low, like when starvation limit hits some would die and turn into a gravestone/skeleton with the inventory items in it.
I think this would make a great incentive to create more buildings fit for each character you manage to get. Also the fact that you won't get locked out of recipes and gameplay but still have to work for it.