If HN has a problem with titles, it's with not enough stores having their titles rewritten to the article original.
People keep saying this, but it would severely limit the utility of the site. When I chance upon a post with more than ~50 comments, I only want to read the 6-7 or so that the community has agreed are best. I perceive a positive correlation between comment scores and quality. That is, the odds that a post with 50 points contains good content do empirically seem to be higher than for posts with 2 points.
In short: I need a comment filter that is more strict than than simply "appears on Hacker News". I don't want to read every single one.
Similarly, if there's a bunch of responses with a score of 1 with replies forking off all over the place, having a visible score lets you catch that at-a-glance and avoid bothering with a conversation that is clearly digressing.
That was in the REPL for a while and I thought it was just annoying and confusing.