I like the idea of categorizing votes. Especially since people will pat you on the back by just ++'ing the node rather than replying with more detailed comments, so you don't really know and don't get as much satisfaction as you would with a more personal feedback.

However, then people would need to explain why they didn't vote, too! E.g. “I found the idea interesting, but found the prose too annoying and unformatted, so it came out neutral.”