I was thinking about a space grand strategy game yesterday, and I was playing with the idea of it being similar to Crisis of the Confederation, a mod for CK2. Basically, there would be a democratic confederation of planets centered around Earth, but the outermost colonies started favouring separatist ideas and then declared independence, causing a civil war called the Crisis of the Confederation. I was thinking if it could be like Victoria, where ideologies play a large role in the game, and a nation's name and flag changes according to their ideologies. For example, the Confederation could become an Empire if their government type changed to some sort of monarchy. And then, during late game, an alien empire could show up and pose a threat. It would be cool.
Another idea I had was a game that was more centered around early space colonization. Basically, you could play as one of Earth's superpowers or private companies and establish colonies in other planets. BUT, unlike other space strategy games, these colonies wouldn't be directly controlled by you. They would be more like vassals, since their distance from Earth would mean that they would develop their own government and culture. Also, a single planet can house several different colonies founded by different nations, and those colonies can fight between each other without their overlords from Earth intervening directly. Say, the UK and Italy establish their own colonies on Mars. But those colonies start fighting there because of resources. Now, both Italy and the UK would finance their own colonies in the war, but if the UK intervene directly, sending their own fleets and armies to Mars to help their colony, then they would be tempting Italy to do the same, and this would escalate into a full scale war between Italy and the UK both on Earth, space and in Mars. Or the colonies could declare independence and create their own interplanetary empire. What do you guys think of the idea?