When fastpass first came out at
Disneyland there were some attractions that had FastPass available. I believe it was POC and HM. What they quickly learned was FP was actually slowing down the lines and they removed it from those attractions.
Fast forward to today and now they are adding fastpass for every attraction. I saw the screens up and it appears there will need to be information added whenever anybody uses the FP+. I can see this adding to the lines.
For example, why the heck is Spaceship Earth getting FP+? There has to be a far sinister reason why every attraction is going to be tied into the system.