Actually, the "easiest" fix would just be to change the wording. Any other move would have to result in coding changes, which could prove to be rather difficult and tedious, depending on what the actual problem is.
As to making evil races too powerful...
Actually a larger problem to me is the rarity that the AI researches Ethics at all, and even if they manage that, the rarity that they build any of the Ethics Wonders (except NLCs, go figure). The chances that an Evil AI would ever build the MCC in a game is so minuscule its not even worth worrying about. Its really just there for the benefit of the Player.
As for balance....its not actually overpowering. That's misrepresentation by players that are either for or against it. For the MCC, in its current form, to be actually useful you still need a strong empire base and economy. Doubling an income of 25BC isn't really going to do much for you if the Good Altarians control 3/4 of the map. The MCC
itself doesn't imbalance the game, contrary to whatever one may like to think.
Also, that kind of coding change would probably result in
every current Metaverse game to be cheat flagged as the game's core files would no longer match. I know for sure that would not go down very well with anyone.
In conclusion, the only "real" issue with the MCC, currently, is some poorly written text.