People are so used to the old system I don't think they even realize its flaws. They are so used to it and have incorporated it so much into their mindset when going to the parks, that they cannot imagine any other way to experience the parks. Try this exercise:
-- Try to pretend that the system that has always been in place was the current FastPass+ system, and that your touring has always been optimized to use that system.
-- Now try to pretend that Disney is going to implement the old paper-based FastPass system in its place.
Do you really think that people would say "wow, this is SOOO much better!!". No, because they were "used" to the old system. Instead, I think there would be mutiny and probably MORE backlash about the paper system than there is now about FastPass+. Here are some of the comments I would imagine one might hear:
-- What do you mean I have to go to the ride first, grab a piece of paper, and then circle back to that part of the park later? What a waste of time!
-- What do you mean that I can't guarantee I'll get a FastPass for my favorite attractions? You mean if I don't get there early enough, they could be all gone? But I was only planning on spending the afternoon/evening at Hollywood Studios -- so, I won't be able to go on Toy Story Mania! without waiting in a huge line because by the time I get there all the passes will be gone? That sucks!
-- What do you mean I can't pick the time I come back myself -- the system picks it for me?? What about if the window they give me is during a lunch/dinner reservation, or during the time I planned to take a break from the park and go back to the resort for a while?
All I'm trying to point out is that people are so stuck on how they've had to bend their schedules around to accommodate the legacy FastPass system, they don't even realize how limiting and archaic the old system really was. Yes, your touring strategy may have to change, but the old system really felt like it was only good for the small percentage of people who liked to a) be in the park all day from open to close, b) have the stamina to circle the park many times over c) didn't mind Disney taking control over their schedule for the day by forcing set times on them d) didn't have anything scheduled in terms of dining reservations, breaks, etc.