after 2 years, I LOVE THIS IDEA. I'm afraid we have to mod this. I'm a programmer, maybe we should make a team..
Personally, I'd love it if different NPCs had different personalities. Maybe there's that one that's really mischevious and constantly gets themselves into trouble. Maybe there's an NPC that's sarcastic and chill, but refuses to get close to anyone. Also, consider: Queerplatonic relationships.
I already feel like I have relationships with these NPCs. They give me quests, they give me rewards, they sometimes even play drums when I'm nearby. I mean what more could you really want? Anything more would just be awkward. You're better off finding an actual friend to play with.
they already have fetch quests in the game and escort missions, with the romance thing all you'd have to do is change some dialogue then boom your fetching gifts for the npc your courting and taking them on romatic dates to the pre-made quest locations in the game. An ally and enemy function in a game like Starbound, since you do travel so much, would be better suited for factions, destroy a floran village, word gets around and suddenly all floran villages dont like you soo much. You'd need a way to make amends though, perhaps someone on the outpost you could pay to improve your reputation, to leave open the idea that this mechanic could have chance of getting your reputation with factions soo low that towns open fire on you on sight.