I'm sorry, but this view is ridiculous. Disney could have worked to make the park more "kid friendly" without sacrificing what made the park great. I was a kid in the 90s, and EPCOT was far and away my favorite park. Then they crapped up Communicore, Imagination, Horizons, the Seas, and World of Motion, and now I more or less can't stand the park. Things like Nemo and Gran Fiesta tour have not increased EPCOT's attendance to the point where you can say changing ECPOT's ideals was a good thing, and attractions like Test Track and Mission: Space could have been added to their respective pavilions instead of destroying them.
A lot of people falsely believe EPCOT was a hated park when it actually stood for something, but the guest satisfaction numbers from the time directly oppose this viewpoint. The reason EPCOT changed is because TWDC got lazy in attracting new sponsors, and when sponsorship dried up, they decided to go the easy route for things that would sell the most merch instead of cultivating original characters like Figment that could do that.
Making every park like the Magic Kingdom, in the long run, will not help WDW.