1) Hire a Benevolent Dictator/Community Manager. Usually the second title is just a euphemism for the first. I will go ahead and state that said person should have some history on HN, should be evaluated on a reasonably consistent basis by both pg and the community, and should have a commitment to be here more often than not. They should be able to cull some stories and promote others not only based on their personal interests, but also to the betterment of the community (even if the community doesn't always agree). I am also willing to put myself up as an applicant for said position assuming pg is willing to work with someone remotely - as much because I don't want to see the argument that no one would be willing to do it as that having run a few BBS and forums I have some reason to think I could actually do it.
2) A full-featured API that would allow members of the community to have more control over how much of HN they view and participate in. As any community grows you get more diversity, and it becomes harder to ascertain a common "always good". Instead give folks the ability (preferably through tools) to modify how they participate in and view the community. If there's a subject that always bothers you, perhaps it's best for everyone if you can avoid having to even see it. If there's something you're particularly interested, being able to see more of it is probably worthwhile.
My .02 worth for you :-)