This is why the advanced bookings should be decreased or removed entirely. Reduce the number to 2, have them both revolving and eliminate the tiers and the unnecessary attractions (Shows, Mad Tea Party, Tier 2 Future World attractions)
No, I like the idea of prebooking as it currently is, except you should be able to choose 3 across any park of your choice (and while I'd prefer no tiers, those are necessary due to the lack of attractions at EP and DHS, and must stay in place until they build more attractions).
However, the fourth fastpass should offer an additional functionality that essentially mimics what FP used to offer. The way I think they should do this is everyone gets to lock in their top three choices and times ahead of time. Then, once you arrive at the park, your revolving FP becomes active for whatever park you are currently in. This revolving FP is completely separate from the bookable FP. Once used, the revolving FP slot is open again and again, though, as the day goes on the availability will decrease for better attractions. If you park hop, as soon as you enter the new park, the revolving FP can now be used to book attractions in the park you hopped to (assuming availability). To simplify this further, I would make the revolving FP not a bookable time, but rather work like old FP in that you get the next available time, which would be displayed on the app/kiosk. This changed would solve all the current issues -- solves the limit of only 3 FP, and solves the park hopping issue.
They should also make sure they separately name these items, so they aren't confused. When you go into the App/kiosk and click FP+, once you are in a park, you are shown two options: Bookable FP and Revolving FP. If you click bookable FP, its business as usual, you get three selections, can change time/attraction, etc. If you click on Revolving FP, if you have one, it shows your current Revolving Selection FP (if any) with option to select/change, if click that, it shows all the attractions for the park you are currently in and the next available return time, which will be your return time if you select the attraction.
The bookable FP still has merit as things might be booked up later, so if you want to do something at a specific time, these allow you to lock it in. Because the Revolving FP return times are less predictable and based on next time and whatever availability remains, this would incentivize people to still use their bookable selections wisely. That's my vision at least. Tom, you listening?