I think it would be a huge improvement to be able to control the defaults on quizzes, and especially to reset specific settings en masse. This is especially the case for people who are transferring from Blackboard. Canvas generally seems to do a great job preserving the previous settings, but there are a couple of properties it has not preserved, at least on mine. One was the shuffled answers, which is understandable because currently Canvas does not provide this at the question level (though I understand that this is changing). The other is the one-question-at-a-time viewing. It would save me a huge amount of work to not have to go back through every assessment and set these.
I have only come across this suggestion one other time, and it surprises me because it seems to me that it would be so obviously helpful.