I’d at least like to be able to choose colors for posters, and auto-collapse some. There are a few very-active posters who basically never post anything aside from confident but poorly-informed flamebait on a wide range of topics (but “HN nice” enough that they don’t get moderated for it, though their threads often get nasty). Making it easier to spot and ignore them would solve most of my problems with HN’s comment section.

[edit] and, flip-side, there are some I’d like to easily be able to spot in large threads, because they’re consistently good.