CodingJack saidSomeone will obviously have to moderate that like you moderate your comments.
Nothing to moderate if the feedback just gets sent to us through email.
No one moderates the star rating, which appears publicly with much potential to change other buyer decisions. In such case, a single line private comment from buyer to author going to be less harmful and most cases it will be helpful. Also instead comment, it can be simple dropdown list to choose 4-5 predefined reasons.
Regardless of above feature, the easiest help Envato can do is just displaying the ratings in splitted manner like this. This actually requires very less work from developer and no one loses anything: