While I'm onboard with the community + software = experience, let's look at the problems.
Let's say I posted a comment, "I love monkeys" and got down-voted to like -10 or something. Aside from relevance questions, perhaps HN is an anti-monkey society. How, from just the score, am I supposed to know that? In other words, by limiting my choice to simple up or down arrows, it makes the other guy scratch his head trying to figure out exactly how his comment was misconfigured for the group. So then he has to plead for somebody to explain that to him. Hopefully, he will get an explanation from somebody who represents the majority of downvoters, but that doesn't have to be the case. He's just as likely to receive advice from somebody, as in this case, who didn't know other huge parts of the community rules.
I love the social networking aspect of the site. But I'm not a fan of the current software as a communication tool between users or as something that would increase (instead of decrease) that experience. BTW, that's why so many "here's my picture of Dilbert" articles are posted -- there's less risk in offending anyone, and heck, you can't figure out what you did when you get downvoted anyway, so might as well go with easy, fast, and funny content over content that might have more substance (and be riskier from the point of view of the submitter)