Need more flexibility in determining which units are offered to the learner - think personalized or adaptive learning. Provide the ability to assign a conditional activity to any unit. The conditional activity feature would enable an instructor to restrict the availability of a unit according to a certain condition such as date, test score, group membership or another unit's completion.
Gregory Reinert commented
See Moodle for an example of this: https://docs.moodle.org/33/en/Restrict_access_settings