I definitely second Paul’s suggestions. I’d also like to see more industries with flat backs like grain silos or coal/ore mines. An older style freight building/depot would be nice too.
As far as non-train related buildings, I’d like to see: a city hall, a gazebo/city park, a drive in theater with concession stands, and a 1950’s highway motel.
I would have also said a church, but you beat me to it with a nice offering!