It seems like there are two major complaints and one other complaint that is a notch lower.
1) Tiering at Epcot, AK and DHS
2) Limiting FP+ to only 3 per day
and to a less extent
3) Needing to plan anywhere from 1-60 days before you go
All valid complaints. And they would be complaints whether these rules were applied to the paper system or the new RFID system. You also forgot the limit of one park per day. That's rumored to be addressed in the future, but that doesn't help anyone who goes before that change is implemented.
The first two are easily rectified by Disney using their existing system if they discover that those limits aren't needed based on the flow. I'm sure Disney will monitor the wait times of the FP+ queues and if they are too fast they will allow more people to get into those lines. If FP+ queues are very long then it means that there is a capacity issue and people are really complaining that more people are using FP+ as compared to FP- which to Disney is a positive.
The first two are rectified by creating new attractions to absorb the demand created by increasing attendance. Instead, Disney has chosen to ration the existing attractions.
My guess is that eventually Disney will allow a floating number of FP+ moving forward where you could perhaps only book 3 in advance but at the park based on minimal queues in certain FP+ rides allow you to book more FP through the kiosks and app. So if I'm in a standby line for SM and check my app about what to do next and see an available FP+ for Dumbo I can grab it. This might allow me get to more than 3 for the day and maybe up to 6 or 7 like before.
This is a huge assumption. If by some strange chance this was implemented, AND the technology worked properly, it's highly doubtful anything left available at that point would be useful/desirable to most visitors.
I guess my main point is that there is no reason that FP+ can't do the same things as FP- but it is better b/c you can use bands and an app where before you had to pull paper.
"Better" is certainly subjective. In January, when the weather was cold, I had to free up my hands to roll my jacket and sleeves up in order to line up the band. This was both inconvenient and quite cold. Also, I traveled alone and don't own a smartphone or tablet, so had no access to the app. I'll be traveling again at the beginning of March with three other people who also don't have smartphones or tablets, and no access to the app. Paper was "better" for me.
The issues right now is that they are still figuring it all out. Sure it will end up slightly different since more people will have access but while Superusers will be frustrated most users will end up better off. So people are very upset b/c they think the current workings of FP+ (which aren't perfect) are how they will be for the next 10 years.
I honestly don't care how it will work in 10 years. I care how it worked at the end of January when I was there spending my money and having my trip affected. I care how it will work at the beginning of March when I will be there with my family, spending my money and it is affecting our trip.
For the record, I didn't consider myself a "superuser" since I go either in September or January with low crowds. I would use FP as needed, which meant on a slow day at AK or HS I might not use any FP at all. But I still felt the FP+ affects.
So instead of sending your complain to Disney about how FP+ ruined your trip and you'll never go back, instead explain the things you liked about FP+ (the bands, ability to see things on the app) and how if they can streamline that with allowing you the ability to find low wait lines and grab a few more FP how that would be awesome.
The bands are part of MyMagic+ and it's sometimes difficult to remember not to lump them in with the FP+ arguments. That said, not everyone likes the bands. The RFID tech is still glitchy. Some don't like the colors. Some don't like anything on their wrists. I'm an adult with a small wrist and even after sizing it down by removing the grey part, it still felt bulky and never seemed to "sit right" on my wrist. Some people wear watches, which leads to an odd choice of either wearing both on one arm, or wearing the band on the right. I can tell you from personal experience that wearing the band on the right makes for an awkward park entrance.
And again, I can't use the app, but from reading comments from those who do, it's nothing to celebrate.
Also, low lines are a thing of the past since rides that never needed FP+ now have it. For example, I've gone in late January for the last 4 years. Pirates has always been walk on, at MOST less than 10 minutes, at any time of the day, but with FP+ this past January it was consistently 25 - 30 minutes, sometimes up to 40 minutes. Same with Haunted Mansion. Even Figment had a wait time, which I've personally never seen before.
Disclaimer - My first trip to Disney using FP+ is in April so I haven't experienced it yet but I will go into it with a positive attitude but certainly understand there will be issues and hopefully in the upcoming months and years Disney will figure out the way to make the experience the best for everybody.