I think the ship has sailed. While not quite "move it's a small world to EPCOT", I've long been a proponent of moving the Speedway style attraction to DHS. I think the real estate in MK is too valuable.
I don't understand why so many people are still attached to the Speedway. It doesn't offer anything unique to Disney, and it's not even a good version of such an attraction. There are thousands of go-kart tracks scattered around the country that are a much better driving experience for kids.
Almost anything they did with that land in the Magic Kingdom would be an improvement.