I find the FastPass brilliant, but again, that is only my opinion
I agree with so many others before me; for ex:
I want to ride Splash Mountain, but the wait is 60 min. We can come back an hour from now.
So it may be time for a counter-service meal, or a showing of the Hall of Presidents, or waiting for the Haunted Mansion for half an hour.
In my hour of wait time, I have accomplished a counter-service meal, the Hall of Presidents, AND can walk on Splash Mt. with nearly no wait.
VS.
I have waited for an hour in line to ride Splash Mountain.
In my opinion, there's really no better way to enjoy WDW. How else do people ride Test Track, Soarin', EE, BTMR, Splash and Space...and things like Peter Pan for the little ones??
When we brought 4yearold cousin Brittney, there is NO way we could've waited in the 50 min. long Peter Pan line. But we COULD ride the Teacups (10 min wait, 5 min ride time), It's a Small World (15 min wait, 5 min ride time), and the Carousel (no wait, 5 min. ride time.)
So in one hour, we rode the Teacups, It's a Small World, the Carousel AND Peter Pan!
(Sorry, I'm just majorly a fan of FastPass!!)
And if they allowed ONLY WDWResort Guests to use FP, that would be terrible on their part. Almost as bad as Six Flags for charging park admission, THEN $25 for 4 rides (no waiting in line.)
Luckily we usually always stay on property, but for ex. we're not this upcoming April. Don't know how we'd do it with those spring break crowds and no Fast Passes!