I think the difference in building schedules is being distorted. In the past 10 years, WDW has opened 6 new attractions: Lights Motors Action!, Soarin', Everest, Midway Mania, Little Mermaid, and the Mine Train. And they have updated many others. Universal has opened 5 new rides: the Suess Trolley, Rip Tide Rockit, Forbidden Journey, Transformers, and Hogwarts Express. Plus they took out Jaws and added Gringotts and updated some others.
I think these things even out over time.
And as someone mentioned, too many Universal rides spin or throw you around. I took my family to Universal in 2013 and we bought a three day pass, but while we enjoyed Harry Potter, neither my kids or my wife wanted to go back on the third day. They wanted to go back to WDW. And they went back to WDW in 2024 and again in 2015.