Calculation of total grade is simple enough to be managed by JS
It can be for rubric. But other plugins can be more complicated and can even require huge data from the database or external sources etc. Plus, MD noticed one useful side effect of the proposed mechanism. In case of fallen browser in the middle of grading, the teacher would find the rubric like "autosaved" next time they came back.
Are we going to track historical changes made to grades?
If we ever implement revisions, surely we can tweak the log reader so that it is able to aggregate records.
the number of points to be written for each cell
Sure, good idea. Thanks!
add a column with total points assigned/maximum points for each row
Hm, that is not very common in rubric examples I have seen. What's that information good for?