I like keeping notes and ratings separate. I like that the notes are generally detailed and thoughtful. I think if we had to make a note when rating a dish, there would be a lot of not very useful comments like "yum."
Also, sometimes I rate dishes that I cooked a long time ago when I happen to see them while browsing EYB. I don't type additional comments because it is been awhile, and I can't remember the details. I like being able to do that.
I would, however, love it if we could undo an accidental rating.