Currently, completion rules work well, but could be enhanced to truly differentiate a self-paced lesson. I propose that completion rules be revamped to include a pathway based on student performance to better differentiate lessons.
Consider this feature from Canvas: https://community.canvaslms.com/docs/DOC-8492
If a student gets a certain score, send them to one path, if a different score, send them to a different path. If a student continually is missing a concept, introduce them to a different lesson.