This was raised and not implemented before previously on MDL-48863 and can see that there was a similar request raised MDL-32089

We have a customer that has asked for this functionality and I have to agree it would be incredibly useful..

In an assignment, we can download all students marks when we used simple grades, but, if we use rubrics, it would be very useful to download all rubrics tables and feedback for each student. In this case, the final grade it's not as important as the individuals levels at each criteria in the rubric.