The ability to promote certain users comments (and vice versa) is good too; but you have to use that carefully.
Would love to have that with the content and users here.
(And then HN replaced that because of the quality of comments here)
I came to HN well before I found Reddit (I think it being mentioned here was the stimulus). [this is my 2nd username here]
HN thrives IMO because it got a high value kernel of contributors early on, through synergy with Ycombinators business, and because of strong moderation heavily focused against new users.
Up until the last year or so most comment threads haven't needed to be filtered, due to the relatively small population, but popular stories now attract a mass of comments such that one can't easily scan through to precis the range of reactions.
HN maybe wants to stay "small" though. A lot of users in any case want to keep a tight focus on start-ups/computer tech/programming; keeping a "clunky" comment system probably provides useful friction to that end.
The main frustration in consuming comments here for me is the lack of differentiation between valuable and disagreeable comments. Though this appears to reflect pg's personal philosophy (he stated that down-voting for disagreement was proper, or words to that effect).
I'm trying to remember if it had the ability to filter comments below a threshold, though I'm thinking it did.
Reddit's comment structure remains by far the best on the internet. You should definitely be proud of that.