It is currently possible to create a multiple fill in the blank quiz question and publish the quiz without designating any correct answer(s). This happened for one of our instructors recently and caused a lot of frustration. The quiz used banks so it wasn't possible just to regrade. The class has over 200 students so adding fudge points is cumbersome. Basically, any student who received that question couldn't make a 100 on the Quiz without the instructor having to manually adjust the grade after the fact. It would be really nice if Canvas warned the user that there were incomplete questions before allowing them to be published. Obviously, not all questions require an answer to be pre-defined; therefore, "incomplete" might have different parameters depending on the question type.
(LOL - perfect case in point: I just tried to save this "Idea" without giving it a title and Canvas wouldn't let me! We need this same functionality on Quiz questions.)