Its interesting that so many issues are already raised before we even consider letting the machines control any physical process. When you add in autonomous weapons, critical infrastructure, healthcare, possibly voting machinery and all the other processes that could be automated, you get a huge can of wriggly things. The potential gains in factory process automation from letting AIs do the planning are so great as to make such use a foregone conclusion. The corresponding potential for unpredictable, even hostile, outcomes is substantial.