Overall I think: dang does an incredible job, the guidelines are great, and the site itself is really well designed.
But I often wonder: Would HN be even better if comment karma scores were invisible? By all means, continue to use votes for sorting, and perhaps continue greying out items once they fall below some threshold (ideally -2 or worse, not zero). But what value does the visible score provide? And does that value outweigh the negatives? From observation of myself and others, having the score visible leads to some unhealthy behaviour.
[0] https://news.ycombinator.com/item?id=239058