pg told me that he wanted HN to look like the output of `top`. The older it gets, the more we approach that goal.
I've never seen a proposed redesign that didn't either add too much whitespace or too little (well, always the former), which makes me think that the current design is in the ballpark of optimal, despite its being unfashionable. Also, HN is very much a text site and that goes deeper than look-and-feel. The first thing most "spruce-ups" do is toss this quality, which compromises the site at its essence and indicates a misunderstanding of what HN is. I'm reminded of Steve Jobs' famous line about how design is not how-it-looks but how-it-works.
If someone did a redesign of HN that preserved both its information density and its textiness, I'd be stoked to see it as an experiment. We probably wouldn't change the site much, because if there's one force stronger than user complaints about design, it's user complaints about design changes. Also, I think it's an advantage for HN to have an unfashionable design, and a huge advantage to have a stable design. Still, I'd be fascinated to see it, and there might be ideas we could use.
The textiness of the site likely scares off a lot of new/non-techy users. Reddit switched from being a text site to a modern UI a few years ago, in doing so they managed to gain a lot of new users. Which in turn ruins the sites community and discussion when users are focused on making cheap jokes and memes for upvotes.
I think I agree with your main point but some distinctions are important. We don't want to scare off new users—we love new users. We don't want to scare off "non-techy" users—they are completely welcome. The users we want, though, are the intellectually curious ones. And there I agree that HN's textual orientation is an asset.