I think the quality of stories on HN is pretty good. What I'd much prefer to see any amount of attention given to is things like:
1) Let me take back a vote. Particularly on mobile, I misclick those tiny arrows a lot.
2) Let me comment inline. Having other comments, besides the parent around for examination while commenting would probably help overall comment quality.
3) Fix the mobile interface. It's impossible to use HN on mobile iPhone and Android handhelds. Making a slightly modified styled sheet with JavaScript is trivial.
4) Support someone making an app, or commission one. As far as I can tell, the current HN apps are all kind of buggy and have little updating. There are lots of young neophytes who'd love to work on this, particularly if sanctioned, and a funded effort would lead to a better product.
These basic UI improvements don't even seem to be on the radar. Also, I'll add, the story-killing on this site is pretty heavy-handed, yet capricious. Same with the title-editing. What constitutes a "hacker-centric" story changes with the mood of the moderators, and the tendency to just change each title to the original headline is misguided. I also think that the special privileges given to YC companies corrupts the whole system.
If there were any other community like this, people would be driven away by the neglected UI and the Star Chamber that governs the content. But there isn't, so there's no pressure to do anything but midnight HN science experiments. I should just pray for some competition I guess...