I've come to the realization that the Play! pavilion is just being put in the wrong park, and were that corrected, it would improve on the surrounding land in each park.
To me, you put the Play! pavilion in the Carousel of Progress building in Tomorrowland and you put the Carousel of Progress into the Wonders of Life building as a new World of Progress pavilion. This way, with the Tron coaster and the rumored Wreck it Ralph attraction, Tomorrowland could easily embrace a cyberpunk aesthetic fairly easily that would greatly strengthen the land. Space Mountain goes down for its much needed rehab and track replacement and can come back with a CyberSpace Mountain overlay. The Speedway gets either a Tron-esque or Sugar Rush overlay. A little handwaving on Buzz and Monsters. Then lots of accent lighting and a ElecTRONica party at night. To me, that land is stronger than what is there now and the Play! pavilion would be a great benefit.
Carousel in Epcot helps cement the identity of Future World to the World's Fair that always will be, by adding another of Walt's 1964 World's Fair attractions to the park (Test Track being the spiritual and architectural successor to the Magic Skyway, and American Adventure the spiritual successor to Lincoln). This is the same reason why it's a small world would work better at Epcot.