I can see some of what you are thinking, but I also think you are creating problems for yourself. I agree that it important to have a curriculum of target aims at all levels. I think yo uahve to be very careful to keep centred on individuality if you do this, though.
I also agree that students should be heading towards being independent learners - able to self-criticise and make choices about practice and repertoire, etc. The teacher becomes mentor and coach rather than instructor. Still, I think an accomplished learner needs a "teacher" as much as a beginner. Yes, maybe less frequently, but again that is individual.
I think the learner needs to have a large say in their decision about having a teacher at this level. However, once they have decided they need the mentor, it is up to the practicalities and the teacher's decisions and convenience must be respected. If you start seeing a student occassionally, it potentially becomes logistically difficult. Your whole schedule then hangs on keeping time available for a lesson every few weeks. I find this very frustrating.
Don't you find that different students have long before 3-5 years decided if they want to learn seriously/Classically or just for fun? I think you might also find this a tricky way of categorising your programme.