I think there should be some more maps such as more Mario Kart maps or City 17. Video game map recreations would be really cool. I don't know or have the programming or modeling programs, but I think that the great community of BeamNG drive could make some amazing recreations, or even maps based on Video game locations. Is anyone willing to make/spread some good video game maps or vehicles? also I think video game vehicles should be expanded because using a combine APC or driving karts from Mario kart or even converting things from TV shows!
It's still under copyright protection. Anything and everything added to the game has to be of the developer's own design unless they get some kind of collaboration deal, but I doubt that would happen. I think the devs want to keep this game in their own universe, which makes sense. There are always mods.
Someone - a third party - made that map. The developers cannot legally profit off of other people's content. The modding community does not make any money from their mods, so they fall under fair use.
