From what I have seen, it looks like Swen has plans for that but I get the feeling that they are prototyping exactly how it's going to work. So the details aren't clear yet, but it seems to be a major goal of theirs to give the companions a strong set of AI to have a life of their own.
I could go either way. I'm also a fan of singleplayer, party based games where you can define the personalities and actions of each member of your party and play it out however you imagine that character. I could see lots of enjoyment with that in this system.
