This is an interesting feature idea! In the fork of WP Pro Quiz (QuizMaster) we’re adding an improved Graduations. Currently in WP Pro Quiz there are graduation levels but they are only used to display different messages. In QuizMaster we removed those graduation levels, because we wanted to make the core plugin simpler. We’ll be replacing that feature with an extension that provides the ability to define different “Grades” such as 70%, 80%, 90% etc. In addition to a unique message based on grades, these grades can be used as prerequisites. As you pointed out @nsaral currently prerequisites in WP Pro Quiz only check if the user took the quiz at all, not if they achieved a passing grade.
We also are building into this an extension for awarding certificates based on passing grades. So the idea of “Grading” is very important to support other features.
