RPG aiming at maturity just can't afford to have karma system. Even if CD Projekt actually manages to make a good one; which doesn't punish you for being bad, it is still a bad desing decision created to hide how a game world fails to react adequately and show you, so the designers have to tell you how bad or good you are behaving.
But actually it's a deeper problem often connected to the main story. There are games in which you can instantly tell which is the 'good' choice and the 'bad' choice. And this actually downgrades the experience to 'Hey, I want to be the white knight". Or total badass. Doesn't really matter, these are childish decisions that totally take me out of the story because I just don't find these realistic. And without being realistic they can't immerse. Just to be clear, by 'realistic' I don't mean our word, but something with it's own inner logic; something I can believe exists. The human mind is just too sophisticated for such black/white stuff.
I am saying all this because it's connected to the karma system. One can't give you points for being good or bad when there is no clear good side, which is something necessary for a story to be mature. If there is going to be a karma system, CD Projekt would have to sacrifice a lot of story complexity. And story complexity is the main reason many of us are looking forward to this game. Just try to imagine Witcher 1 or 2 with a karma system.