The companions can be taken over by AI already in certain situations.
If you're wielding the Shattered Flail, for instance. You have a chance to go mad, at which point the AI takes over your character. (which will almost result in that character using a sleep potion)
If you sacrifice one of your companions to the kua-toa fish folk then the AI takes over that character.
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I'm not saying that any of that means what you're asking for is possible. I don't know. But it's probably worth pointing out that such things exist in the game currently.
Of course the AI is capable of controlling any character. The question is could it control companions in a way that wouldn’t be completely frustrating to play alongside with. That’s a harder issue.
