I wouldn't agree on the needlessly protracted.. Where Epcot is located is kind of awful for new buildings outside of the berm. That's why there's very few support facilities outside of Epcot proper and the areas originally cleaned up for construction.
The expansion of Energy is going into one of the areas that wasn't dug up, pumped dry, and filled. Read the stories of building Epcot's lagoon - it was a nightmare. When people talk about the "swamp" it's referring to Epcot. MK was built on what is generally a more suitable spot of land.