opsimist
IMHO, we need a bait. Something, that will bring in smart people, and only smart people. HN detracts regular people, because it looks boring and doesn't help to continue discussions. This is good for HN, but bad for discussions (and spamers).
I'm thinking about mix of a court and wikipedia. Something, where we can play our game (who is right? who is the smarter?) on steroids, something where we can layout our arguments, facts, ideas, and then discuss them (flame all night long), until someone else, an arbiter, will read all that and declare a winner. IMHO, a topic and number of win/lost/unfinished discussions will be a good indication of smartiness and expertise in a domain.
There are plenty of options to separate smart people from regular crowd. IMHO, a separate DNS server, which unlocks alternative Internet, is the easiest way to move away from regular people, because it's a bit complicated to switch DNS on a mobile device.