I love the NPCs in this game, and I love building, but one of the things that's a little disappointing to me is how little in-game motivation there is to build colonies. It's much easier to get crew members just by running errands for existing villages, and the rewards the NPCs give for their rent are not really high enough to be worth the effort--especially not after the game has gone on for a little while and I already have lots of money. But I think there's a fairly straightforward way you could make much more motivation to build colonies, and make the activity of doing so much more exciting and rewarding for the player: Set up a quest-giver who gives colonization quests. You can go to the quest-giver and they'll tell you a tale of woe: Planet Xorxibotanica just succumbed to the supernova of their star and 8 colonists are requesting help resettling. Your job is to build them a colony with homes for 8 colonists, meeting some other specific criteria (maybe they want to live on a desert planet since that's their native environment, maybe they want at least one guard tower, maybe they want an eggtop garden adjacent to their town, maybe they want furniture made of meat). The quest-giver would give you special colonist deeds, so that when you place the deed, the NPCs who spawn are the particular ones tied to this particular quest. When you complete the colony satisfactorily, either the head NPC of the colony thanks you and rewards you, or you go back to the quest-giver and the quest-giver rewards you. A natural option for the quest-giver would be someone associated with the remnants of the protectorate. It's natural that what's left of the protectorate should be striving to set up human colonies for what remains of the human race, and once the protectorate has a colonization program set up, naturally other races in need of resettlement help would be allowed to benefit from it as well. The reason this would help the game is that I think most players will find it more motivating and engaging to be told that some people NEED A HOME, than to just decide to build some houses so they can charge rent for them. (Those who disagree because they dislike do-gooding will still be able to use the existing colonization system.) Also, since the quests would set particular criteria for the colonies, it would mean that each colony you'd build would be unique and you'd be forced to experiment with different approaches to building. It's commonly recognized that a few artificial restrictions often help people to be more creative and to enjoy the creative process more. There should also be some kind of stat-keeping or recognition of how many colonists or refugees you've resettled, so that there's some long-term reward in addition to the trivial whatever-you-get in a reward bag for completing the colonization quest. There should be, somewhere, written down, how many refugees you've resettled or how many colonies you've built, and you should be able to gain ranks as a Protectorate Resettlement Technician or whatever. The rank could be relevant because the quest-giver would give only really easy colonist quests at first, but then more difficult and high-reward quests would become available once you've established yourself and gained ranks.
I really like this idea, especially the suggestion to implement it alongside the current colony system rather than as a replacement. Perhaps there could be a 'Colony Requests' board at the outpost where you could get colony quests, and have it update with a new quest daily like many of the other Outpost features. More difficult planets could give higher rewards due to the higher challenge. Finally, a reason to visit toxic ocean worlds!
As it stands, I have no motivation to build a colony; designing buildings in these kinds of games is not my strong suit and there doesn't seem to be any particular reason to do it other than if you feel like it. If this was added, however, I'd definitely start building settlements.
