"I disagree" might be split into subcategories (e.g. "fallacious") to not leave people guessing, like I've been left when I've received mystery downvotes. But on thinking about it, posts that get downvoted for wrongess don't generally have a single reason for it, and downvotes might be categorized falsely if there's some social reason.

So I revise my earlier prognostication - mo' categories is maybe not mo' better.

You can't so easily define Quality, even as you can extract some of its well-defined aspects.

I know: allow people to highlight paragraphs or sentences of text that they like, right-click them, and rank those highlighted sentences (or portions of text between two periods or bullet points or numbered points) from -10 to +10.

When someone highlights a specific portion of the text, they get to see what "Less Wrong" users think about it. Right-clicking allows them to contribute their input. This might be a dog to program, but geepers, it sure would make Less Wrong look even Less Wrong. When the ranking dropdown appears, a comment field also appears, when the rank (ie: +8 or -2) is selected. If "zero" is selected, it would still allow a comment.

PS: I'm curious to know how many less wrong users are "small-L" libertarians, how many are "voluntaryists", how many are aware of the history of jury rights erosion in the USA and commonwealths, and how many participate in electoral politics. Of those who are not libertarians, I am curious to know how many believe stealing is wrong. There, that oughtta inflame everyone. Feel free to email me or call me to discuss strategy for making the USA more free. I believe this would amplify everyone's entrepreneurial efforts thousands of times, if we could accomplish it.

How about not allowing voting unless a reply is made? Then downvoters would be pretty well forced to say what the problem is. Spam and trolling could be handled with the report button.