You know what, I don't think that FP+ needs to be so horrible.
There are aspects of it which make me pause and which I don't like. Mainly the reason for it being there: As @
articos recently explained so well, the project was not thought up in order to enhance the guest experience, but rather as a resource management system. Trying to distribute parcels as evenly as possible - the guests being the parcels here.
And this is what makes me wonder how well it is going to work. There is a reason for long lines forming at certain attractions and not at others. Some attractions are just more popular. As others have pointed out, someone who is at Epcot will want to ride Soarin and won't settle on Journey into Imagination instead.
However, and I think a lot of this depends on the implementation, if this system does what it is designed to do and levels out wait times, I think it can even add spontaneity back to a Disney day. If they manage to reduce my wait time at for example BTMRR by about 15 minutes from 40 minutes to 25 minutes, I would not mind waiting in this line. I might have to pay for this by waiting 5 minutes longer for PotC, HM and the Carousel, which otherwise would have been only 5 minutes wait and now are 10 minutes. The bonus would be that none of the lines was prohibitively long for the standby line. So, if FP+ really achieves the standby lines becoming more accessible again, I would consider this a win.
It will also be nice to be able to get FP+ without having to backtrack through the park and for a time that is convenient for me. I don't like the 60 day in advance idea though. I think the reason why they will never go for a much shorter period (personally I think day before would be fine, too) as the shorter the period, the more people they would have accessing the same days data and that might cause problems I could imagine.
There is one thing that becomes much more difficult to do though with FP+ and that is multiple rides on just the headliners. But I guess that is really one of the things that are intended. They want to spread out the capacity at the headliners to more people. Kind of the way it was before FP ever came to the parks.