Honestly, I'm not sure they need to do anything else beyond what is planned to get a big bang for the 50th. The pent up demand plus Harmonious and Ratatouille will probably be enough to drive bookings quite substantially though the next year and at some point Tron will open as well.
I'd love to see them have a light parade as well but I doubt having one would really drive reservations all that much. I think the bigger boost would be for guest satisfaction and future trips but not sure modern Disney thinks further ahead than the next fiscal quarter.