Uploading a large number of courses , the POST request to actually create the uploaded courses can be very long; and there is no visual feedback to the administrator. This can be made much worse when also restoring from another template course.
(For exampl, uploading 100 courses while enabling restore from a quite large course took some 50 minutes, and died after successfully creating 71 courses only.)
A visual progress bar (like the one when restoring courses) would really help knowing that things are progressing; maybe only if the "restore from idnumber-specified course" functionality is in use.
An alternative to this strategy is to go totally asynchronous, and create adhoc tasks (one per course) and let them get run by the cron, while informing the user. It needs extensive work though.