I've thought about this, too. In particular, I'd like to, say, separately up vote "substantive" and down vote "agree". That said, how complex do we really want the UX to be?

As for "didn't read", if you're not interested, just move on. If you think the article is inappropriate and can, flag and move on. If you see a comment that looks like the poster didn't read the article, you can call civilly call out what is in the article, and perhaps down vote the comment.