Not sure if Moodle ever want to implement this but to me I think this make better sense from usability perspective. When you delete a entire course category (say Summer 2005), currently it will prompt you for "confirmation" (see screenshot), then after you click on "Yes" button it will just move all the courses under that category into the parent category if there is one, or into "Miscellaneous." Ideally, there should be a option here on this screen to allow admin to really delete all the courses under that course category. Just my 2c.