If they ever do decide to construct a third park, I think a modified “Westcot” park would be their best bet. It should bear some resemblance to Epcot's World Showcase, but with scaled down pavilions, and I’d group the pavilions into six "continents". Also like World Showcase, there would be a central lagoon, but it would be much smaller than the one at Epcot. It could feature characters and elements from various Disney and Pixar Animated films, and could borrow attractions and theming from the World Showcase, Animal Kingdom (Asia and Africa), and Disney Sea (Arabian Coast and American Waterfront).
The entrance and the northern most land would be Europe, and you'd enter the park through a Norwegian castle. "Main Street" would start with medieval German architecture and gradually become French and Italian Renaissance. To the west and east of Europe would be North America and Asia, and South America and Africa would be in the southwest and southeast. The southernmost land would be Oceana, consisting of subareas themed to Australia, Antarctica, and Polynesia. This land could have a volcano similar to the one at DisneySea, which would serve as the "weenie" of the park. A roller coaster in Asia could be themed to Mulan, a raft ride in Africa to Tarzan or Lion King, and a flume ride in South America to Emperor's New Groove.