Not really. In the question of AI balance it's was about a disproportion of Yor and all the rest of them. That, afaik, isn't as disproportional as it was meant to be. What IS as disproportional as it's meat to be is the AI in "suicidal" games.
Both the balance between Yor for AIs and Yor for players is equally "borked" (not equally in measure, but rather equally in founding principals that define the measure of it's belonging to borkedness...).
And the question of whether or not it is worthwhile to fix it is, quite prosaically the question of popularity and "vocality".
Judging by the forums, and by the dev's "focus history" SP is already a higher priority issue for them than MP.
Judging by common 4x practices "cooperative" multiplayer holds a much bigger "share" in the genre than competitive.
Judging by the hype spreading mechanics and even commercial moves of certain companies, the "suicidal" challenge-lovers are a big element in commercial ecosystem (despite the fact that they are NOT the majority of customers).
It is on the ground of theses assumptions that I estimated the priority and likeliness of "suicidal" AI rebalance to be well above the priority and likeliness of competitive rebalance.
And about the cap prevention. I'd have to slightly disagree.
IMHO there needs in fact to be some "buffer space" for them to overbuild their population into. I entirely agree that it shouldn't be a way to stack insane bonuses. But there needs to be a "one project worth" of buffer space.
Yor can populate their planets by building, which is a plus, but they also must populate their planets by building which is a minus.
The mechanic of building a colony ship for an organic race is simple - build and lose population, wait for it to regenerate, build and lose more.
The mechanic for synthetics is build and lose, replenish, build and lose.
Synthetic mechanic is different in that it is more effective the more people there already is on the planet. So for example doing it in the order of "assembly->colony->assembly->colony" would be faster than "colony->assembly->colony->assembly". There's no such difference for organics but there is such for synthetics.
Specifically let's say it's 15. jumping 15->13->15->13 would be slower than jumping 15->17->15->17 . Even if there was no benefit of having population beyond 15. Without a buffer however this build order would be impossible for the capped pop level but still possible for any lesser pop level.
I can't really give strong enough arguments why it should work the same at all pop levels, but it would simply not sit right with me if it didn't.
It's not a question of balance, just more or less a question of consistency.
If I was the one choosing I'd make them able to order an "overbuild" at any time, but never actually let them have more than pop cap + the size of their biggest unlocked assembly. And of cause reduce the numbers till they are back to the cap just as they are now. Or maybe even better - as long as the associated shipyard isn't making a colony/transport cut it all back down to pop cap in one turn.