I've also thought about an A-E Ticket style Fast Lane system (I think that's similar to what you're thinking) and the biggest issue would be how guests keep track of how many points/"tickets" they have left. Is it entirely a phone-based system that shows your remaining point totals or is it wristband-based with kiosks available for guests to check their points. Refunding points could be accomplished by enacting a "prime then process" system where a scanner at the entrance "primes" the pass (checks that it has enough points to be used) and a scanner at the merge point "processes" the pass (takes the points out of the account). Anyone in the FL queue would not lose their points as they exit the line and anyone past the merge point would be given an immediate return ticket to come back and ride (since their points had been deducted). I think being able to earn a free Single-Use Fast Lane would be cool, though I don't know how that would work with the new Perks & Play system. 

At least this could (potentially) solve the issue of the FL people crowding into one or two rides at certain times of the day, hurting the experience for everyone. In October I saw what a full FL queue does to the standby line at the end of the day on Siren's Curse. What an awful experience that was.   Not that anyone asked: but I've thought about how to improve the system for awhile. My admittedly flawed idea is that each guest has Fast Lane points or credits. Small rides use 1, bigger rides and most coasters use 2 and a small number of high demand rides need 3. Single day guests are given 2 or 3 points for free. Passholders also get a modest amount for free for the season and can earn more in different ways, similar to perks. Outside of that, they are bought in packs and are connected to a (preferably RFID) wristband. Obviously there are problems with this (like having to refund points when a ride shuts down or how it doesn't first people to spread out to different rides) but I think it creates a more fair system that lets everyone feel like that have a chance at using it.

Again, for a Madhouse

Is this similar to the TapuTapu system that Volcano Bay just got rid of? I'd think a better system would be to keep the wristbands and have a system that lets you scan it at a kiosk. Basically TapuTapu but with disposable wristbands instead of reusable bracelets. That might be closer to one of the original FastPass systems, but the idea is there either way. Some of Great Adventure's big coasters have in-line lockers (I think at least Flash, Jersey Devil, and El Toro have them). Batman, Superman, and Skull Mountain don't have in-line lockers IIRC. I don't know about Nitro's locker policy. I'm against forcing guests to use their phones while also forcing them to get a locker, but it's much better if there are free in-line lockers.

caveat emptor