It'd be rare that I would look at notes for upvotes, but if one of my nodes has a significant number of downvotes, I want to know why.

This is just an idea to help people think before they vote. I fully expect that there would be fewer votes cast. That may also mean that XP becomes a more meaningful indicator of community acceptance of a node.

I'd be unhappy if my participatory node-resorting feature were removed to replace it with your acceptance-metric. This brings up the related question - most of the time the vote total on any node is hidden anyway. Most people don't sort nodes on reputation (I do). This means that neither of our outcomes are helping these two other populations (people who don't vote / can't vote (the other 2/3rd of the population that is anonymous for instance), people who aren't logged in and haven't chosen to sort by rep).

I am voting neither up or down on your post because you have a valid comment, but you do not offer any other solutions. ;-)

Maybe you can help figure out a way that would provide more information to the people reading the nodes? As a reader I would like to know if someones post is incorrect.

As a reader you typically don't know what the vote totals are and even with the vote totals they won't tell you anything about the quality or accuracy of the comment. I have not heard an idea about this "problem" which won't be a royal pain in the general case. I don't want to have to send people private messages when I vote. I don't want to have to write public messages when I vote. I don't want my access to positive or negative votes restricted because I'm not interesting in justifying my every action.

Generally I vote because I liked/disliked something, agreed/disagreed with, am annoyed with the person, am annoyed with the thread, am being deliberately contrary to someone's expectations (this is usually a -- vote for people who complain about -- voting), or most commonly am just exerting some control over the sorting of the nodes in the thread.

It appears you are responding to an imaginary complaint about downvoting. My complaint is about people who do not post corrections to others incorrect posts, instead they only downvote. Downvoting somebody for incorrect information does not help the community, b/c no one else can benefit from it, unless you are sorting by rep which as you've said 2/3 of the visitors can't do.

So downvote randomly if you feel like it, I don't care. But if you are going to downvote a node due to incorrect information, please post a comment.