In a nutshell: I would like to see who is up- or down-voting and a specific reason for that.
As you all know voting is done without giving any specific reason. People do not state their reasons for up- or down-voting, but this might end up effecting the overall reputation of a user in a negative way:

• If you are a good problem solver but the majority does not understand and down-votes him, people in general will ignore him, so good solutions will tend to go unnoticed.
• if you are a not so good problem solver but the majority up-votes him, that solution might appear as though it is a good one, although it might not.

There might be other cases I cannot think of right now. My point is that this might end-up in a non-inhibitory & unchecked feedback cycle resulting in loss-loss situations where both the problem solver and the other users loose.
Describing a short reason why someone liked or disliked a particular post/solution/suggestion will provide a good feedback for its owner, and showing who voted for it will enable a productive conversation between the voter and votee. I know this is not a trivial issue, I would like to hear what you all think.