I sympathize with your feeling that a negative score is a bit bewildering, but I don't know that additional stats would help that much. (Though, on the other hand, recently I got pounded down to -2 and then up to +3, and I probably wouldn't have a clue why I was up at +3 if I didn't understand it was an over-reaction to the original down votes...)

Anyway, I think the real trouble is that you just don't know the reason people are voting the way they are. Does that -1 vote mean they objected to my techincal content? Or maybe it was my tone? Did they think I was drifting off topic? Maybe my writing was unclear and they just didn't understand what I was saying?

The obvious (though not necessarily right) solution would be some sort of slashdot-like selection of canned explanations ("+1 insightful", "-1 overrated", etc.).

The less obvious solution: just get rid of negative voting. Put the emphasis on the positive, and if someone disagrees make 'em post a reply explaining their disagreement.