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.
If HN has a problem with titles, it's with not enough stores having their titles rewritten to the article original.