Well, bio gestalts uses migration network, so biohive's critical mass is overcrowding + 10 unemployed drones, then, via migration push 100, all pop growth is sank to planets with migration pull, if empire has any. That's why I kept Spawning Pools and Clone Vats on fully developed planets, that you can see on the screenshots above.
As for all this thread in general.. is this a thread to discuss suggestions/ideas, or just another we-whining-together thread?