Thought provoking ...
Personally, I don't think there are limits for those that want to control. There are limits of control that a society will tolerate, I believe we are very close to that limit.

I believe that an AI would just be more efficient in that control, but certainly not any more oppressive than humans are. Torture or death by AI would be no worse than torture or death by a human.

Total control by AI might actually be more humane, but then again, a super AI, after learning, might decide to reduce the number of humans to a minimalist population as technicians to maintain the AI.

Good questions you ask. We cannot know until this "breakthrough" happens.

btw think you might find this interesting.
https://www.nationstates.net/

Read More, Reason More ... JTS