I’m thinking, and I feel like it would be cool if we not only had our one planet to colonize, but what if we had an entire solar system of linked planets that a player can spread to after they have started to produce starships. That could actually be a campaign, to colonize every planet and accomplish certain goals.
You could have three types of solar systems: one for “sol” or our solar system, which would contain all of our real planets, another for a pre-built fictional solar system Containing fictional planets like abandoned world, and a third Solar system that uses rng to generate a randomized system with any combo of planets, fictional or not.
As for the resources required to maintain multiple planets, I would suggest just treating each planet like you treat each map in a region and just process statistical data in all inactive planets. It’s inherently inaccurate as we know, but it gets the job done and adds to the gaming experience
As for the first systym, “sol”, i think adding a blastfurnace/mercury type planet, a Venus/high atmosphere type planet, and helium and methane has giants would be feasible. Asteroid planet would be Ceres, which is a dwarf planet in our asteroid belt, and ice planet would be Pluto.
I think you could use Europa for the underwater planet, and a Dyson sphere map would just be a special station that has to rely on power itself to survive. One other thing that would be cool would be titan. Sure, it’s a cold planet, but it’s not an ice planet. Most of its atmosphere is made up of organic materials like methane, and it has actual lakes of propane. Even that sand that covers Titan’s ground is made of organic compounds. You could give it a yellow-orange hue and make the planet your system-wide gas station. I can imaging it being as brutal to play as ice world.
Anyway, these are my ideas, let me know if you have questions.
Quick idea: What if there were some "disputed" planets/solar systems that weren't inhabited that multiple commonwealths or players could try to take over for themselves? This is where the idea of Colony Wars comes in: have multiple players wage out an epic war to gain control of a planet and its resources. The requirements for participation are that you must be independent, and that you must have already colonized your own planet. After the war, to ensure that nobody else takes over your planet, you have to build a DEATH LASER on your home planet. Just kidding. There still should be some sort of mechanism that prevents players from taking over someone else's starting planet. By colonizing a new planet, new buildings and options are unlocked like a (specific) interplanetary teleporter (like the planetary equivalent of the bus station) and resource transfer between planets. Sorry if my ideas are a bit vague, but those are just my thoughts on this.