I agree with Ka1man, that it will feel strange if you have an companion with an own personality but you can control him yourself. example: One of your companions is a dwarf who dislikes humans and who fights for the freedom of the dwarfs. But when you control him you let him answer in a way that he betrays the dwarfs and cooperates with the ones who enslave them. But If you play your own char later and give such an answer, your companion will camplain and he says that he will always fight for the dwarves, no matter what.
I see 2 options, but I do not like both: - Like Pillars of Eternity, you can control all chars and use their skills, but only the main char talks in conversations and makes decissions. ( It will not be like this from what I have read.) - You main char has all options to choose from (In the example above he can be for or against the dwarfs, no matter if he is dwarf or human.) but when you control your companions you can only choose answers that are not against their personality. (This will take away freedom from the player.)
As I have said, I am not really happy with all of these possibilities. But I do not have a better idea.
Prof. Dr. Dr. Mad S. Tist
World leading expert of artificial stupidity. Because there are too many people who work on artificial intelligence already