If the fiends could be controlled and lived happily with like you are suggesting, Ryll, then the humans would never have needed all that bullshit brainwashing, conditioning, gene manipulation, and hypnosis treatment, or culling out the undesirables. Half of the show was about making a point of how absolutely necessary it supposedly was for a stable society (or let's say a society at all) to bring up the children with absolute, and ruthless, care or none of them would survive. That's why the adults were so afraid of children, as absurd as it seemed.

And now we are supposed to believe the queerats can pull it off? One look at that abomination's face and behavior was enough to reveal it must have killed hundreds or thousands of queerats before it got to these villagers - or it's a huge plothole.

Nor do I believe the fiends (humans) would anyway live too long under the rule of queerats. Superior ability breeds superior ambition, like they said in Star Trek. They wouldn't suffer happily a rule of rodents much weaker than they.