I think being able to customize lots and the sims world anyway you like is the most important. If you look at Planet Coaster terraforming it is amazing and most players can spend hours just playing around with the terrain tools.
I would like to be able to make my own beach, waterfalls, mountains, a park or forest with a river running through it with a bridge built over the river. The possibilities are endless.
I think terrain tools are very important and a big part of a game where you can play God.
