Yeah, I don't think it's "not working", I think largely it's a new system guests are unfamiliar with and unwilling to adapt, and the fact that a lot of people can't grasp the concept of a queue-less line STILL MEANS THERE IS A WAIT BUT YOU'RE NOT DOING IT STANDING ON CONCRETE IN THE SUN.
People throw temper tantrums when Facebook changes their layout, for crying out loud.
I wonder if something closer to a fp+ system could work, though? Where when you get in the park, your tapu tapu is preloaded with the aqua coaster but then you could schedule a specific return time for, say, 2 other rides in other tiers at a kiosk or from the band itself? The first screen tells you the time you're able to ride the Coaster (predetermined by your entry time in to the park). Second asks you to choose a ride between like honu ika moana, the volcano body slides, oh yeah/oh no. Third lets you pick between the mat racers, etc?