I wouldn't even do that. The only way to limit FP is to charge a premium for it. Follow Shanghai and charge $100 per person for 8 attractionsNot that they'd listen to me but what I think they should do with FP going forward is:
1) Get rid of the reservations and turn it into an app/kiosk based version of the original paper FP system. Use the same rules that you can only hold 1 FP at a time unless the return window is over two hours away.
2) Have a maximum number of FP per day for each person. Maybe something like 4 for guests not staying at a Disney Resort, 5 if you are staying at a Disney resort. Then sell add-ons at like $5 per FP if you want more, charged as you book them in the app.
To prevent the popular rides from running out of FPs before 11 AM, they can only distribute return slots for a capped amount of time from the current time. If you made that cap 3 hours, for example, no ride could run out of FPs until 3 hours before closing.