For many years I was a fan of FP, since I knew how to maximize FP usage.
Now I'm of the opinion that the theme parks would be much better places for "guests" if FP was completely eliminated.
FP does not increase ride capacity; it only changes how wait time is distributed. One person gets to wait less time meaning that someone else has to wait longer. Of course FP increases Standby line wait time. It's basic queuing theory.
Instead, WDW is going in the opposite direction, giving us FastPass
+. Now even more attractions will have preferred lines, meaning longer Standby lines. I dread what's going to happen at PotC and HM.
You can't market "no FastPass lines" to customers. FP+ is all about marketing, not improving the "guest" experience.