FP+ is being implemented. The question is what happens when it fully rolled out, guests who make a resort reservation are given full information regarding FP+ at the time of their reservation.
The system has been live for resort guests since November. Overall awareness will certainly rise over time but Disney is going to great lengths to educate incoming guests. We have a late-March trip scheduled and received a boxed flash drive with
MDE info, a postcard reminder and multiple emails.
All incoming guests know what is happening...unless they are ignoring all of the above.
We know the current (OK OLD) system treated every guest who entered the park the same. A person doesn't have to try the new system to know they don't like the difference.
People will always form opinions but some appear to be more informed than others. In the case of FP+, opinions seem to be largely tainted by assumptions made in lieu of experience.
You nailed the reason why some people don't think much of the new (OK current) system. The fear it will have the same issues as the 180 day system for dining reservations.
And this is the big source of the incorrect assumptions, IMO. In a single operating day Space Mountain, Soarin, Everest and every other WDW attraction accommodates FAR more guests than "Be Our Guest" does for dinner.
I've been regularly monitoring FP+ availability for a month now...dating back to Martin Luther King Jr holiday weekend. The ONLY attraction that regularly poses problems is Toy Story Mania. It often fills-up around 12-18 hours before the next day begins.
Right now...at 11:30am on Tuesday...TSM is no longer available for today. (Of course, under the old paper FP system all tickets would also be gone for today.) Tomorrow, TSM is still available. It's also available all days through the busy President's Day weekend which starts in 3 days.
The only other things which can present a problem are fireworks and parade viewing. Limited availability leads to them filling up day-before. Popular character meet-and-greets tend to fill up early same day.
Right now, here is the full list of attractions and experiences which are no longer available for booking today:
Ariel meet
Enchanted Tales with Belle
Wishes viewing
Illuminations viewing
Toy Story Mania
Mickey & friends at DAK
That's it. People can walk into the Magic Kingdom at noon and still get FP+ for Space, BTRM and Peter pan, with multiple times available for all.
Even when more people (day guests) are added to the system and crowds higher, there's still plenty of capacity for the rides to absorb everyone. Space Mountain, Soarin and others can accommodate 30,000+ guests in a day. Simply put, there aren't 40,000 people hopping online to try and grab a Space Mountain FP 60 days before their trip begins. Every park..with the possible exception of DHS (TSM) has a wide range of experiences which will appeal to different ages and tastes. The high number of FP+ experiences, limit of 3 per day and tiering at Epcot and DHS will work to preserve flexibility.
Those who plan in advance--perhaps just while drinking their morning coffee at 8am--will probably have a better experience. But in terms of flexibility, I don't see how this is any worse than the old system which forced guests to go out of their way to claim paper FP tickets and then circle back at uncontrollable return times.