I believe it's going to have presence at both existing parks, similar to Harry Potter, with a Pokemon area rumored for Florida and a Zelda re-theme for Lost Continent.
They will then build the actual Nintendo world area in the third park that will feature the Mario Kart ride plus some other rideable attractions, most likely also including a Donkey Kong family coaster.
It’s certainly an exciting time in Orlando over the next 5 years with huge expansion going on across all the parks. As reminder of the huge amount of announced projects and those rumoured for next 5 years in addition to previous mentioned universal rumours-
Star Wars Land (feature 2 E ticket rides) Hollywood studios: 2019
Minnie and Mickey’s runnaway roller (Hollywood studios): 2019
Sky Liner (DW) 2019
Harry Potter coaster (IOA): 2019
Terminator replacement (universal): 2019
New illuminations (epcot): 2019
Tigres (Busch) 2019
Sesame Street (Sea World) : 2019
Ratatouille (Epcot): 2020
RMC (Busch) 2020
Guardians of the galaxy (Epcot) late 2020/early 2021
Tron (magic kingdom) 2021
Rumoured:
-Launched coaster (SeaWorld) 2020
-Mary poppins flat ride (England area Epcot)
-New country in Epcot, current rumour suggests India with major jungle book e-ticket ride utalising the pirates ride system from
Shanghai.
-replacement ride at magic kingdom for stich
- Mexico boat ride at Epcot rethemed to Coco
- couple of possibilities being Explored for Animal Kingdom- either expansion of pandora with another major ride or Indiana Jones area to replace Dino USA areas
-new addition/s to volcano bay in 2019/2020z