There is no such thing as prefection.. There is always a flaw. To be honest I can't believe we are still arguing (Not the scientific way of arguing,) About the Centralized Control. I lost my manuel a long time ago but according to the books yes the cerebrates had to follow the Overminds commands but they still were their own beings. I wouldn't even call them efficent with how they consumed. They tried to have control over the genetic coding and forced it however they could true but still they consumed everything and didn't give organisms time to adapt on their own outside of the swarm where a mutation could prove better suited than what the zerg currently has.