I think that the moodle activities inside a course should store relative times instead of absolute ones.
Then the time to perform each activity in a course should be relative (for example 4 days after the beginning) to the course start time or even the student enrolment data to that course.
Allowing different students performing the same course in different but overlapping periods of time, but following each of them the same rhythm.
Also a rhythm could be stated so, the same course could be performed a 50% slower by some students (for example full time or part time students)
But these are only my thoughts