I too am pretty confident same day FPs will be available. So all will be grand for the PP. As long as when they end the day in Epcot, they are happy getting same day FPs for Nemo and Maelstrom.
This is how I feel.
It appears to me that some of the concern about the 3 FP+ per day plan seems to be that all the good fast passes will be taken up by the plus users and there wont be any left for guests who choose to use the current fast pass system. What if Disney has taken that into account with their data crunching and have determined that both the plus and the current fast pass program can run concurrently and provide more people with a positive experience. That could be why they changed from a test plan with 4FP+s per day to the proposed 3FP+ per day.
For the sake of simplicity, lets divide park guests into two groups:
1. The limited guest this is the guest who is limited by wants or needs, i.e. they dont want to stand in a line for Space Mountain for two hours or they have young kids who need a nap or to go to bed early, for example
2. The unlimited guest they can make rope drop, can split up for the mad dash to get fast passes, can ride everything they want, twice, by 11am because they know how to work the parks, can participate in EMRs, and are able to stay all day in the parks, if need be, to get the best use out of their fast passes
Right now WDW has many features in place for the unlimited guest. The fast passes, early and late hours, parades and fireworks and shows that get the crowds away from the rides. All of these features help to disperse the crowds throughout the parks. So what about the limited guests who would like to be able to ride TSM in the afternoon without having the whole family show up at rope drop? Maybe they are from the west coast and rope drop is just too early for them. Or the limited family who would love to see Enchanted Tales with Belle, but their three and five year olds, along with grumpy grandpa, dont want to stand in a long line.
It appears as if the FP+ system is planning to improve the park experience for the limited guest. This new system could work very nicely for those guests. The limited guest might be a rather large percentage of the daily park crowd. And trying to improve their experience would be a big Win-Win for both Disney and the limited guests.
But they can't afford to increase the satisfaction level for the limited guests by decreasing the satisfaction level for the unlimited guests. Disney would want both groups to enjoy their parks, because both groups are valuable to them. So I would think they would try to make sure that the new plus program doesnt make the whole experience worse for everyone. That is why I dont think that the plus users are going to use up all the available fast passes on any given day. The system would be adjusted to prevent it. Right now the current fast pass system uses up all the fast passes for popular rides, so why would they create a system that would duplicate an existing problem? I don't think that is their goal. They would want to create a more equitable system that satisfies the most people. And I think they are trying to do that with the plus system. If it doesn't work, then it will be back to the drawing board.