It will be quite useful to have below mentioned feature in moodle quiz - plugin
1.
Allow student to give public feedback against each question: A student
can suggest a better way to solve the question or point out a mistake in
Teacher's solution.
2. Allow other student to reply to
student feedback: If a student posts a query against a question in
comments. Other Students/educator can help him resolve his query.
3. Allow upvote and down-vote comments: This will help to filter relevant and updated comment.
4.
Allow student to sort most up-voted or most recent comment: For ease of
finding the most relevant comment against a question.
5. Monitor comment for any slang/abusive words:
6.
Block a particular student from commenting: Block a student from
commenting in a particular course if he is found using abusive language
in comment.
7. No effect of delimitation and collaborative
with quiz/page : It should be collaborative with existing quiz activity
and should not delimit any of existing capabilities of quiz.
8. Comment should appear as block against each quiz question: for ease of use and understanding.
9. Allow only deferred feedback: The comments should be visible to a student only after he has submitted the quiz.