FP+ can be a major advantage for groups in they use the system to it's potential. I agree that this actually hurts the majority of park guests, but it 100% can be an advantage. During july 4th week (busy week) last year I was able to do the following in 1 day at MK.
FP+: Splash, BTMRR, HM, Pan, 7D, Meet Rapunzel/Tiana, LM, Meet Ariel, Dumbo, Teacups, Pooh (x2), Buzz (x2), Meet Tink, Meet Mickey and Minnie.
Along with non-FP activities: Sit down lunch, FoF Parade, Small World, Meet pluto and Daisy, Meet Donald and Goofy, Pirates, Aladdin, Jungle Cruise, COP, and HEA
IF FP+ was not around that day, there is no way I would have done that many things. Sure my Small world wait probably would have been shorter, but that was a 20 minute wait (longest I waited in line all day). I even had another FP for Pirates after the fireworks, but we decided to leave.
Loosing FP+ will be a huge bummer to me and honestly may make me consider alternative vacations. I really do view it as a major advantage after I was able to do that in MK and very similar success in the other 3 parks.