Poor writing is not a new thing, of course. Most of the moderation mechanisms that it uses were perfected a quarter century ago when sites like Slashdot were popular as a defense mechanism against bad user behavior. Bad user behavior impacts commenting, article submissions, and moderating itself. While bad users now have AI to abuse, the problem of a large volume of low quality content is is largely the same. The moderation mechanisms end up targeting the problem at the source: identifying good and bad users. So, the same amount of bad users generating a lot more garbage isn't that big of a deal. Getting good karma still is a lot of work and it makes identifying all the garbage created by users without that relatively straightforward.
Using LLMs to tag, flag and filter content might not be a bad thing to experiment with. There are a lot of low quality AI generated opinion pieces that somehow make it to the front page. Same for political and controversial stuff, which of course is against the HN guidelines for content. Auto flagging things that obviously violate guidelines should not be that hard. It's just a matter of having good guard rails. @dang might actually already be doing that. I know I would be if staying on top of piles of generated garbage was part of my job description. It might also be done to give good content a little boost.
The new articles section has a very low signal to noise ratio currently and the window for good content to make it past that is very short. Often articles on the front page will have many duplicate submissions that never made it past that. IMHO duplicate submissions should just count as upvotes on the original. Auto de-duplicating based on canonical URL should not be that hard.