I don't really mind optional party members, but I can't say they've been handled well by PB in the past.
Considering how many resources it takes to develop proper characters and party AI, I agree with JDR that they should focus on what they're really good at.
I've never really played PB games for the characters. It was always the world, exploration and immersion. Gothic and Gothic 2 also had just about the perfect difficulty curve - so I'd like to see a return to that kind of balance.