That's how the old FP was, though, and only the very top rides booked way far out like that. In the above scenario, I think you'd likely be able to get pirates and/or HM early and, unlike old FP, you can start booking addition LLs as soon as you tap into the first one, so having a later Big Thunder doesn't hinder you picking up more once you use morning bookings.
Also, MK never used to be tiered, so it'll be interesting to see how that impacts availability there. With only being able to prebook one mountain, I would expect all of the mountains to still have good availability day of, at least until people start tapping and grabbing.