Paper FastPasses used to be a great help. We were able to rope drop, get FPs, and do pretty much every ride in the park easily. I was always the designated FP runner, racing back and forth across the park every time we were eligible to get another FP. On one day, I got 7 sets of Toy Story FPs. At MK, especially, we NEVER had to wait for anything. It wasn't difficult to collect 10-15 sets of MK FPs.
Now (if you're not staying on site), the FPs are only marginally helpful. We were there two weeks in early December, and checking 30 days in advance we were not able to get FPs for any of the newer attractions (Flight of Passage, Na'vi River Journey, Mine Train, and Slinky Dog Dash). Several others (Toy Story Mania, Soarin', Test Track, and Frozen Ever After) were not available on most days and only times that didn't help us on other days. We ended up using FPs for second-tier attractions that ten years ago were often "walk on" (but now aren't). Even some of those second-tier attractions had poor FP availability. Many times, we didn't even get three that were useful.
We adjusted our plans accordingly to minimize our waits. But in doing so, we accomplished quite a bit less than we used to be able to do.
Looking up numbers, I see that MK attendance increased from 17.23 million in 2009 to 20.45 million in 2017. EPCOT grew from 11 million to 12.25 million. AK grew from 9.5 million to 12.5 million. HS grew from 9.7 million to 10.75 million (and closed about half of the attractions). On average, they have 20% more people in the parks every day than they did less than a decade ago. With the growth in attendance, they really need to open up a bunch of new high-capacity attractions. (And I'm talking about ADDITIONAL attractions, not just closing some and building new ones in the same space.) And as much as I like FP, I think FP just exasperates the situation. When about half of the people riding are using FPs, it takes twice as long to move the standby line through. That's why many attractions (like Spaceship Earth) that seldom used to have a wait now have fairly sizeable wait times now that they have a FP line.