How about dispaying the rounded log(score)? You give some indication of how well a comment is doing but it's hard to vote strategically.
Not that easy with negative and zero scores, obviously, but those usually aren't the comments people are looking for.
This makes me think it would be good to remove the name of the commenter as well as the number of points a comment gets.
Started logs. [f(x) = log(x+1) or log(x+3)]
Short "i agree" or "i disagree" type of comments are usually discouraged on HN, as they don't really contribute to the discussion. Usually.
Also, username hiding is a good idea in some cases, but I think it's worse overall. It encourages snarkiness, some posters are actually worth looking out for (grellas on legal threads, pg on HN, etc), and it makes back and forth discussions difficult to follow unless you give each user a unique ID per thread. Impersonation can also be a problem. Overall, I think it adds up to more problems than it solves.