It seems to me that your suggested policy would result in comment-placement effects being even stronger than they are now. What score should a comment end up with if 50 people consider voting on it and they all think it should have a score of +2?
I communicated poorly. I don't think "should have a score of +2" should enter into the decision to upvote, downvote, or not vote. Instead, I'd rather voting algorithms which, when implemented individually, have results which can be meaningfully summed. For example, suppose everyone upvotes exactly when they think a comment is in the top 5% of comments in "everyone should read this" ordering and downvotes for the bottom 5%. Then the sum reflects the number of people who read the comment x (the average percentage of people who thought it ...
From this 2001 article:
I, at least, found this amusing.