There are times when quizzes are used in more in-depth ways than simple MCQ, for example when students are given a scenario then asked several questions relating to it, usually made up of different question types.
It is critical that the component sub-questions are kept bundled together sequentially so that the student can easily refer to both the scenario and their previous responses. With the current functionality these questions must be arranged manually onto pages, automatic 'x-questions per page' cannot be used, and it becomes problematic to reassemble if the questions are located within a question bank and pulled into a new quiz elsewhere.
If the quiz had an option to assign parent/child status to questions it would solve this issue, by keeping the linked questions together for page display, backup/restoring and importing of questions, and would also enable categories containing this sort of linked question to be used with random quizzes.
In anticipation of one query about page structure - I would envisage that a parent-child set of questions would always display together on one page (with no other questions), overriding the x-questions-per-page setting unless that setting is 'show all questions on one page'.