Have you considered a STUDENT ONLY suggestion box at your studio? Suggestion boxes can be a wonderful way to get feedback from customers, and just their presence alone makes the business appear to be amenable to improvement, which is a positive in the eyes of the customer. But a STUDENT ONLY suggestion box is taking things to another level, because the message it's sending out is that, as studio owners our number priority is the happiness and welfare of our students. They are #1. I think that's a good message to send. And I think it would be empowering to our students, to be able to request and suggest betterfications to the studio.
Try it for a month and see what comes through. If anything, it would be an interested experiment to see what suggestions are put into the box.