Your idea is very nice, but also very heavy on the development requirements.

I'm gonna take the approach of the minimum development work required.

Currently as far as I know (correct me if I'm wrong), Earth is the only place where you can use and trade for solars. You could get away with never trading for resources or modules by gathering and making those yourself. But if you want access to any of the Shipyard services or Crew you are tied to going back.

Player trading is very limited, if not non-existent. And the use for solars is tied to Earth or QP conversion only. Changing this would require quite a bit of work, although it would probably be a good thing for the game? Not sure. Having more uses for solars would definitely be a plus.

Having access to the Shipyard and Crew services outside of Earth would be a big improvement to the game. It doesn't have to be player owned, it could be manually placed in the world at key locations for less actual work required. Other Earth services could be included.

Going a bit further would be to let players, or corporations, set up their own Shipyard or other services, either for public or private access.

Even further would be letting players trade with each other and be able to set up static services on stations. Resource/Module trading and Shipyard services could be included. At this point Manufacturing structures such as ships, stations and fortresses could be an idea.

Player-owned or not. I feel like the obligation to go back to Earth for any transaction or modification is a big hindrance to the ability to explore and be independant in the game.