There has been discussion of this previously, but very little. The comments on the mathoverflow post indicate that there isn't much consensus about the target audience. I haven't reread them all very carefully though, perhaps there is some more tangible result there that I missed.

I've also talked with at least one person about the subject at the meetups and we disagreed and didn't really resolve our disagreement.

So I agree with you that the question of "who should be on Less Wrong" is an open question, and it is a question which really should be addressed.