I actually want to see them think a little outside of the box, bring us an interactive AR themed Luigi's Mansion. I think instead of go-karts I would rather they bring that anti-gravity from MK8 to life in a dueling coaster that starts off side by side but takes two different paths(1 through Shy Guy Falls and the other through Bowser's Canyon). As for Zelda I would like to see them bring Skyloft to life and you have to ascend up on a loftwing (skytram) to reach the elevated city, populated with shops, characters and what-not. To then experience a simulated sail cloth experience as you leave descending down to the main Nintendo attractions. I just want it to be like a full experience that takes you into a portion of these video game world's we've been playing for so long.

I'll say a Splatoon theme ride simular to the Buss Light Year ride in Tomorrow Land or the Toy Story ride in Hollywood Studio. You spray ink to battle Octigons.

I put real life examples of similar attractions in brackets.

Peachs Castle for Restaurants, souvenier shops and co. ( Magic Kingdom )

Zelda/Ganondrof big roller coaster: ( Flug der Dämonen )

one "dark" roller coaster (in building) themed by f-zero or Metroid ( Space Mountain )

Small Mario Coaster for younger Children ( Small roaller coaster )

Star Fox Shooter Coaster. ( Buzz Lighteryear Shooter )

One themed explorer boats tour (Pokemon) ( Jurrassic Park Ride )

Splatoon themed wild - water ride (where people from the outside can shoot with water guns)  ( MR Popeye Ride )

For the big attractions.