Moodle provides a really bad interface for grading many assignments. Therefore we started the moodle-destroyer-tools.
At first this was more a tools to merge csv-data, but now it uses the moodle-api directly. So moodle-destroyer-tools are now more like a wrapper for moodle which offers a json iterface for moodle.
While json is a great joice for data-transfer, it is not that great for writing detailed (multiline) feedback.
moodle-destroyer.el converts the
gradingfile.json from moodle-destroyer-tools to emacs
org-mode for grading.
After finishing grading, it exports
org-mode back to json, so you can upload the gradings via moodle-destroyer-tools.