We are experimenting with lots of practice material, and it would be awesome if students could see feedback after each question rather than having to wait until they submit the quiz. Because we want the feedback to be as immediate as possible, if they have to wait until after the quiz, then we need to keep the quizzes super short–maybe 2-3 questions, and even that much delay is not ideal. However, if they could see immediate feedback, then quizzes could be any length.
Here's why it would make a difference (aside from being able to have longer quizzes):
It would allow us to require students to type in their answers rather than choosing from a list we provide. Active/productive learning is always better than passive/receptive learning.