The system has more down time than the previous Fastpass system ever did. The user interface is unnecessarily complex. Beyond that, there is a large population of people that feel scheduling 60 days in advance is a ridiculous premise.
Please quantify "large population". Please quantify the amount of down time on the system vs the old.
You speak of opinions as if they were facts.
I know full well that there are also people that appreciate the guarantee that they can get onto an attraction, but in many of those cases I've found that the people are only satisfied because they are ignorant of the alternatives. When I ask people what they think of the Fastpass+ system they seem to be highly in favor of it. Then, I explain to them what it replaced and their reaction has universally been, "wow that sounds a lot easier" or "why did they change from that?" I have seen most of the surveys Disney has put out there regarding Fastpass+ and I have yet to see one that asks for a guests opinion while comparing it to the previous version.
Do you think that potentially your obvious bias against the current system might taint your explanation of the old vs new system enough to make someone who does not know anything about it believe it was something it was not?
For example, here is me describing the differences between the two systems.
Back during the FP days, most parks you needed to be at at rope drop if you wanted to ride your favorite ride without standing in line. Then you had to run to the attraction, literally run to TSMM in order to hopefully get a FP before they were gone. One time I had to split my family up, me running to TSMM while my wife and kids ran to Jedi Training Academy. When we met back up, I had a FP for 8pm, the last available time, and that was the exact time my kid was able to get into Jedi Training Academy. We were stuck with the FP.
Once you ran to one section of the park, you might find out that your FP was not for hours to come, so you had to find other things to do to kill time. Maybe you ride the local rides, shop, etc, or maybe you go to another section of the park and come all the way back at your appointed time. If you had a late FP, you were stuck with it, no matter if you decided to hop to another park, you were starving and wanted to eat instead, or you just felt like leaving. Use it or lose it. Stand in line or stay until your FP time is there. There were also rules as to when you could get another fastpass, and you had to keep track of a pocket full of paper slips. Hope you didn't get on Kali and forget to stow them safely!
In the new system, you can preplan as much or as little as you want. If you know you want to go on a few specific attractions that are quite popular, you can do so, you just need to book it in advance from your computer or cell phone. Most rides do not need advanced booking FP+ except in the busiest of times, so you can feel free to just grab a couple you may want while you are booking the ones you REALLY want, and feel safe in knowing that at any time between then and the moment you are standing in the park, you can change it to another ride, or another time. You are not stuck with anything. Just like dining, you have a few "must do" attractions that you know you want to hit, and book accordingly. You can change things at any time, I've been in line realizing I won't make a FP time and in a minute or so, shifted it to later in the day. I did this so much on my last trip that it was the most spontaneous and stress free trip in a decade.
Now, I went to extremes here obviously to paint the picture I wanted to paint, but no matter if you agree with my over the top assessments or not, you hopefully can see that bias can paint drastically different pictures, whether you mean to or not.