I can't remember which 4x space game I played that had this, but what if there were random planetary/system/empire wide plagues that must be cured (toggled on/off in game settings)? I like the idea of having to design a hospital ship or a hospital ground team that you have to deploy. Also, I like the idea of having to research the cure for each plague before getting rid of it completely. Of course, this idea might be too on the nose given the current ongoing global...situation.
Also, I like the idea of adding research to increase growth rate somehow. It would give us another option other than assigning governors or just moving pops to new colonies. I suppose the medical ship or facility in my first idea could go along with that, but it could also be a flat bonus research sort of like the terraforming rate increase. It would be kind of neat if those research projects were things like "Cure Cancer" as that would be incredibly satisfying in my opinion, though I suppose it would make it kind of opinionated as you don't always have to play as human, so alternatively, it could be "Cloning" "Prolong Serum" etc.
Edit: Ran into this thread shortly after posting this:
http://aurora2.pentarch.org/index.php?topic=12225.0Thirdly, there could be research to increase the max pop for your colonies as there isn't any mechanic that already does that, as far as I know. It would be awesome if there was end game tech that allows you to move planets, modify suns, etc. in order to make planets even more suitable (without going into SM), but that's out of scope for this thread.
Lastly, (and this is really for Steve if he happens to read this
) I would love if gene modification was reimplemented as I love the idea of having thin boned and tall asteroid people and thick/thicc heavy worlders.