The Mimot don't need to be nerfed - nothing in the above suggestions make them more fun to play. Rather every other civ needs to be similarly OP in their own unique way.
That is not at all realistic. I don't care how creative you are, there aren't 15 unique ways to make each race OP. Can't be done. You need a combination of buffs and nerfs to create uniqueness. Part of the fun is figuring out how to deal with each race's flaws. If there's never any challenge then it's not much of a game. I might as well watch a movie.
With all due respect, I vigorously disagree. Videogames haven't really done this, because they've gotten into the mindset of being obsessed with "balance" - which tends to lead to little flair and lots of generics. (videogames also suffer from the feature of being able to modify post-release, unlike board games). And I agree, when a game is linear, the game needs to be balanced on that linear featureset, otherwise it becomes unplayable.
But with a game like GalCiv - how many outright ways are there to win?: Conquest, influence, Diplomacy, Research, Ascendancy. Whether you want to throw "prestige" in there too or not is up to you (a "balance" victory, basically?). And how many strats within each potential victory condition?
I'm not advocating for making Civ XYZ awesome at all 5 victory conditions - clearly that's ridiculous. But if, say, you make a race twice as good at influence (ie the Krynn), does that make them win every game? - no. Because being awesome at influence does not win you the game alone.
I suspect that the issue with the Mimot is that their 2x ships ties into more than one of the above systems in a very easy way to utilize, and thus seems very OP. On the other thread you discuss how the Onyx aren't really that great (in so many words) despite their crazy strong ships because (again, in so many words) there's more to the game than having good ships.
I did mention above that food seems to be a mechanic that's pretty useless at the moment. "Implementing food" may go a long way in bringing to the fore the problems with the Mimot's rabbit-rate-of-reproduction. After all, they suffer the problem of Rome, expand for food, or die. (and Rome died).
If you're into Board Games at all, I highly recommend you check out "Cosmic Encounter" it's a terrific example of there being no balance whatsoever, and every alien race (there are like 200 different ones, IIRC) is just COMPLETELY broken. At face value you look at every race and say: "what the hell, this is so f***ing broken, how can this not win every game?" But every game is a toss-up. Because there's more to winning than exploiting a single OP mechanic.
This is just my opinion, obviously, but perfectly balanced games suck to play and get boring quickly... The answer to a strong mechanic that works isn't to nerf everything to some generic baseline, rather it's to make more strong mechanics..