Now, explain how all of these things would have been better under the paper FP system. Or, when there were no apps at all,
MDE or otherwise?
You don't NEED to use your phone for any of these things. You just need to use it if you want to take advantage of some of the features of the new system.
Remembering the times - easy, we only had "remember" our ADR time; any fast passes were automatically given to us as paper slips and thus in our pockets, so nobody had to whip out a phone.
Headliner with no wait - again easy - why would we have gotten paper fast passes for it to begin with, if we arrived at the ride and it had a 5-10 minute wait? We would have simply boarded through the standby line. Only if it was a ride we LOVED would we have gotten a paper fp to return later and ride a second time - since with a line that short, we could reboard again through standby essentially as many times as we please. Nothing in this process would require a phone app.
Disney has just closed the ride for rain/broken - well, if you had a paper FP for it and just got rained out, your paper FP is now temporarily useless - HOWEVER, if they do return the ride to service later in the day, you can get on even though the window has passed. Thankfully though, with no 3 pass limit, you could skip right down the road to get a fast pass for some other ride. Again, no phone required. Now, you are given an electronic omni pass which requires you to use the app or a kiosk.
Disney has just seated you 1 hour late for your table service, overriding your FP return window - again with a paper pass, all you had to do was explain to the CM what had happened and they'd let you in when you got there. We would just bring the receipt from the restaurant to prove we were there, hand over the paper fast passes and go ride. No phone app or rescheduling required.
Again, now, if you need to make any changes to your assigned 3 FP+ for any of the above reasons, you MUST pull out your phone or go stand in line at a kiosk. There are no other options; Cinderella's fairy godmother is not going to pop in and handle it for you.
Until you've been there and lived it for 10 days, you won't get what a pain it can be. And if you happen to be so extraordinarily fortunate as to spend 10 days onsite juggling reservations and FP+ and run into no problems, you still might not get what a pain it can be for many other guests who don't beat the Murphy's Law odds.