You can get on more rides if you BUY express. But for the same money ($0 since FP+ is free), which means no express, on a busy day you can get on more rides at Disney. I can go into MK on a busy day and use FP+ to get on some key rides (Thunder Mountain, Peter Pan, and Splash Mountain) that have higher lines. Then fill this in with lower lines (under 3o minutes) all day like Haunted Mansion, tea cups, carousel, etc. Then use the last 2 hours of the park opening when lines in all parks go down to get in other things like Pooh, little mermaid, POTC, etc. So first 5 hours is FP+ and filler rides and then in the last 2 hours you can easily get in 4 or more rides. I am not joking when I say we were at Uni for 8+ hours and got to ride 5 things (2 of them are the train). We could have done a 5th at the end but my sister was tired. We did stop and eat once and got a quick snack (chips & butterbeer) along with a couple bathroom breaks. We could have probably got 2 (plus the 1 at the end) if they wanted to do a couple shorter lines like Mummy and Twister. But even at that we are talking 8 rides and 2 of those was the train each way so really 7 unique things.
The issue is Universal has less filler rides (c and d ticket) that have lower lines. Many of the rides never went below 45 minutes even at the end of the evening. So I think this is a product of lines being inflated by express, not being able to utilize express if you are going the free route, and not having smaller interesting filler rides.