A gigantic field would be bad, but why is the assumption that this central area had to be this gigantic array of post-shows and well-groomed plazas? The park's true attractions are laid out along the out edges of an hourglass whose interior spaces could house entire theme parks (one's with better layouts and mercy on your feet.)
Epcot broke the mold, but not in any good way. There's no real transition from parking lot to world of the future. The park's centerpiece isn't in the center. Its center is a fountain plaza that offered little sense of time, place, or direction. The bulk of this park is and has always been massive amounts of pleasant spaces with nothing in them. The array of walkways and planters that make up Future World East and West could fit another respective Communicore crescent within each. What's worse, you could literally fit another entire Communicore within the massive gap between it and the lagoon. Is that good design? How long does it take to get from Imagination to Canada or TT to Mexico? What do you encounter along the way?
Once there, you've become trapped in a literal loop. It's all laid out so linear that there's little sense of discovery or exploration. Just a series of themed cul de sacs wrapped around a massive body of water.
Certainly any good park needs some nice "inbetween" spaces, but I think Epcot Center over did it.