I was going to say the art but since you are already working on it here are same ideas
1- random events that can be both helpful or harmful
2- a way to change the difficulties , as much as I liked the game it was hard to get used to it at the start ,it wasn't a big problem for me but I can see why same people may not gave it a chance it deserves
3- maybe also more choses to make , more places to go , more ways to get happiness and power