I would like to suggest a location in the Speedgrader for the teacher to leave notes about a student for themselves.
Arguments are too vague. John needs to make more specific points.
Then the following week if John has taken your advice and you see the improvement you can write him a note in your feedback.
John, great job narrowing down your topic. Your writing has improved from last week. The point you made about XYZ makes your essay more persuasive. The point could be made stronger by...
Providing acknowledgement of improvement is motivating for students. Making feedback personal is critical to creating a feeling of connection in the online learning environment. I feel that this tool could facilitate the enhancement of the educational experience.