Who has a answer for a system that will make the vast majority of people happy?... So if old FP was not the answer and new FP is not the answer what is?
The answer lies up the road...
The answer is in having NO method of virtual queuing; but, instead have enough quality attraction capacity that wait times remain reasonable on their own. This is the only method that would make every guest happy. Old or new, FP of any sort will ultimately yield the "have and the have not" discrepancy. Those in stand by queuing will always feel slighted in seeing someone bypass their wait in line. Unfortunately, the virtual queuing genie can't be put back into the bottle; so, let's attack this from another angle - what purpose does FP serve and to who's benefit?
It's very naïve to think that FP/FP+/ExpressPass was created for the guest's benefit in terms of actually making their day more enjoyable. The concept of multi-tasking was borne out of the need to keep everyone in the parks waiting in the same lines for a majority of the day. How long of a line has always been a byproduct of "popularity" and capacity. Popularity is determined by how much value a guest places on the "worth" the attraction yield to them - is it an A,B, C, D, or E ticket in their mind. Capacity is how quickly the attraction can chew through that line. Very popular attractions can have very short wait times if the capacity is high enough or the opposite can hold true.
At the end of the day, FastPass was born out of necessity. The popular Disney attractions remained popular and guest satisfaction was impacted and their revenues were impacted by guests being tied up in long lines. The choice to try a virtual queue was obviously tantalizing enough to make the attempt. Relatively inexpensive to implement in comparison to rolling out another attraction worthy of drawing crowds, FastPass was born. For Disney, the ROI would be high because the perceived value to the guest would be high.
FastPass (paper) sorta worked. People bought into the concept of being able to do something else and come back later. The reasons why it "sorta" worked is best explained by why FastPass+ isn't.
The key differences between FP and FP+ in regards to the guest acceptance, if you boil it down isn't the shiny technology you use to interface with the system. The geewiz "I'm making a reservation from my phone" coolness is simply a perceived value. Whether the reservation as in the virtual world or a physical ticket, it doesn't impact guest satisfaction (except when the technology fails) like the two big differences: virtual queuing on everything & reservations in advance.
Virtual queuing on everything means that every ride and attraction has standby capacity impacted. With the old system, the only impact a popular attraction's addition of a virtual queue would have on a less popular attraction is if the potential guest on the popular attraction entered the standby line for a less popular one. Now, every attraction has their theoretical capacity reduced by virtually queued guests directed their way. The perceived value of a shorter return time is the carrot that is driving guests to these attractions that didn't use to draw a crowd.
Reservations made in advance is the other driver in the issues guests are having with the new system. Vacations are fickle thing. As much as you can plan your day, life interferes. Maybe you wake up feeling ill. Maybe it rains. Maybe you take too long to eat. Whatever the reason, every vacation doesn't go according to plan. This means that not every FP+ return time is being utilized. The difference is that this is happening with a reservation made prior to the guest ever stepping foot into the park, let alone made "shortly" before the guest decides to experience the attraction like the old system. To compensate for this, FP+ overbooks the available slots and when that overbooking fails and everyone shows up - the line increases. Of course the same can happen the inverse to the standby guests "advantage" when people don't show up and the estimated standby time is less than advertised. The key difference between the old paper FP and the FP+ system is the reservation choice was made days before the moment of truth instead of within a "reasonable" window where the individual is more probable they are going to fulfill their reservation.
It's these two points that are reason why guests aren't in love with FP+. I'd contend if you took both of these off the table and just use FP+ on the old rides that had FP with the new tech, it would have a higher degree of acceptance than the old system as the need to "run" to get a paper ticket wouldn't be an issue. Of course if this was done, then there really wouldn't have been a reason to spend money on FP+ as there would be no value gained for TDO. Which brings us back to why it was done to begin with.
In their minds eye, FP+ was cheaper than putting in enough quality attractions to draw the crowds away from the current popular attractions. The are banking on the perceived value of selling a person on "a short wait time on a Disney Mountain" that you can "make from your mobile device" and you can "reserve it days in advance". Their hope that this promise is enough to keep guests happy. Of course the sad reality is that when the time comes, you may not be able to make that Mountain reservation and if you do get it, you may miss out on a bunch of other attractions that you use to be able to fit into the same day because they are now busier with people steered to it. Of course, if you can't do it today... you can come back tomorrow.
*which is exactly what they want.