Thoughts from the grading trenches

I'm supposed to be grading opinion essays right now. The rubric is right here. If I thought it was appropriate, I could leave my feedback to them as a comment, to go along with the feedback they're getting from their readers. Our revision policy is out there, too.

This is all public. The only reason I don't make my feedback to them public is because I like to be a little more ... nit-picky than what I feel is appropriate for a public comment. I could very easily email my feedback to parents so they can discuss it with their students.

So why have I been led to believe that if I give their essays a number along with my feedback, they will be more informed? What does the number add? If I just gave a number and no feedback, how many parents would complain? A few? But what if I gave feedback and no number?

What am I missing here?