As others have said, it's a losing proposition to try and make the argument that WDW is better. That whole better/worse binary establishes an argument where a discussion could be, and then no one wins. That said, you could make a compelling case for visiting WDW. How about visiting WDW as a point of personal comparison? A lot of pp have made good points about the immersive experience of WDW, about its size, about the attractions and parks available at WDW.
I don't have much to add, except this. Perhaps because DL enjoyed Walt's close attention, it feels a bit more like Walt's personal vision and seems to reflect the modernist culture in which it was originally built. WDW reflects a collaborative vision, and seems to reflect the postmodernist culture in which it was originally built. So when I visit DL I feel it is "authored" by Walt, the individual. When I visit WDW, I feel it is inspired by Walt. The difference is subtle but, yes, it makes a difference. And I see them as complementary, not competing.
WDW was built in a "What Would Walt Do?" spirit. Walt died shortly after acquiring the land for WDW, a place with enough space to hold and experiment with his many ideas. He never got to see them come to fruition. Instead, those who believed in his vision and in his memory built Walt Disney World. For instance, Roy put off his retirement to realize Disney World and it is Roy who insisted on renaming the resort WALT Disney World, so that we would never forget the man behind the magic. At the same time, WDW is the resort that reveals the Disney in us all: Roy, the Imagineers, cast members, and guests. So what we see in WDW is not Walt's vision but his legacy, what others see and value in the Disney vision, what others contribute, and what we collectively embrace about it.