I only skimmed the last few pages of this thread, so ignore me if this has already been mentioned...
I was a "tester" over Halloween weekend. Not once did I see any indication that FP+ or MB was in "testing" mode - I was given notice that I was getting MBs and if I wanted to customize them, I'd best get on it. Apparently there was some fine print saying I could skip the MB and go with the traditional KTTW, but nothing ever jumped out and said, "GUINEA PIG!" As a DISer, Floridian and APholder, I already knew about this stuff, but I was irked, nonetheless.
That said... I didn't think the system was that bad; not as bad as I expected, anyway. Some things worked well; others glitched. When things did go wrong, like a disappearing FP+, I was able to quickly and easily fix it.
But the big thing I took away from the experience was the post-trip survey. Clearly, based on the questions asked, Disney already knows an awful lot about what's working well, what isn't and what guest expectations are. I sat down to take the survey, ready to vent away and tell them of all the things I like and don't like about FP+, MB and
MDE... and found that they'd anticipated every single item on my list. How the MB feels, works, looks. The myriad ways FP+ can screw up, how I feel about booking before my trip, my thoughts on how many FP+ a day is good, and whether or not I preferred the FP- system. How MDE worked for me at home, in the parks, in our room, on my phone, on other devices, at kiosks, etc. 99% of the issues we're talking about on the DIS? They already know.
What remains to be seen is what they do with the survey data. I wouldn't be at all surprised to see some things we feel are permanent fixtures change dramatically. My advice at this point to travelers is to try not to stress, assume more will change, and do your best to roll with it. I suspect this will be a work in progress for a long time... and shoot, maybe that's the intention, to keep tweaking on a regular basis indefinitely.