@Chirine and @Leslie,
Have you considered using the new Diary plugin? It is a souped up version of Journal, with the added capability of starting a new entry each calendar day, but also able to go back and edit previous entries, depending on how the teacher set up the Diary activity. When the teacher rates and gives feedback, an email is sent ONLY to those students who received a new rating and/or feedback.
You can see it in operation at: http://m3x.drachels.com/course/view.php?id=4
Send me a private message if you would like teacher access.