It would be nice to have a new type of problem that can occur between colonists as added realism. Loneliness.
Think about it, colonists mailing other people (and spending money while doing it) by just giving it to a mail rover. And people working in a mail office or something like that using paper, which could be a new material made from wood, and putting it in a postal office to be bought by colonists.
There could also be cars in the game. They would be cheap and simple. As fast as a rover but can transport a colonist anywhere, or multiple colonists in a bus or van, without them getting tired.
This can lead to car washes and will cause more loneliness without them because they can't drive to other people's houses or the postal office. And there could be other buildings for community to join together like churches, party houses, maybe even just placing a simple bench by a park for two people to talk.
3 idea in one post:
the first is original ,mail rover can be a good idea but if you add too much thing your support burn or explose in a big boom (only if you use a nuclear réactor)
the second is the transport
it is the most sugested idea in the game (i think) and bast haven't add it,find why
and the last work with car but can add a center of repair for rover
I don't know if there are emergency rovers or fire stations in the game yet but that could also be used to prevent fire