My $0.02 (apologies if it's already been said; I haven't read all the comments): wanting to do Internet-based outreach and get new people participating is kind of at odds with wanting to create an specialized advanced-topics forum where we're not constantly rehashing introductory topics. They're both fine goals, but trying to do both at once doesn't work well.

LW as it is currently set up seems better optimized for outreach than for being an advanced-topics forum. At the same time, LW doesn't want to devolve to the least common denominator of the Internet. This creates tension. I'm about .6 confident that tension is intentional.

Of course, nothing stops any of us from creating invitation-only fora to which only the folks whose contributions we enjoy are invited. To be honest, I've always assumed that there exist a variety of more LW-spinoff private forums where the folks who have more specialized/advanced groundings get to interact without being bothered by the rest of us.

Somewhat relatedly, one feature I miss from the bad old usenet days is kill files. I suspect that I would value LW more if I had the ability to conceal-by-default comments by certain users here. Concealing sufficiently downvoted comments is similar in principle, but not reliable in practice.