I think this would make more sense if comment karma, and link karma are a different (like on reddit). For example, I have nearly 1000 karma points, but most of those points came from links I have posted. And then there is bob who has 500 karma, but has never posted a link and most of his karma comes from contributing to discussions. I pass the 1000 point threshold, and now I have the ability to decide whether bobs comment is good enough to be live when I haven't proved that I can contribute to the discussion.
