This would mean Star Wars and Kingdom Hearts exclusivity for Nintendo. Disney Infinity, Kingdom Hearts 3, Fantasia: Music Evolved would not release for the other next-gen consoles but instead get released on Wii U only. The new Star Wars too, it was a new Battlefront right?
With Disney-exclusivity it would make more casuals flock to 3DS and Wii U to, I think. Disney is good at advertising their stuff. Nintendo's stuff should be heavily advertised on Disney-owned channels, while Disney's stuff should get a heavy showcasing on Nintendo's platforms. Allow some higher-up from Disney to do a Nintendo Direct in America ;D
It would be the other way around too, Disney should be allowed to make cartoons and shorts about Nintendo characters and series. With the Disney seal of quality on it, this can't be a bad thing for either company. Disney is good at making merchandise too, so while there is already a whole world of Pokemon merchandise, Disney should be able to make good money out of other Nintendo franchises like Kirby. Kirby plushies? Oh yeah.
With Epic Mickey, Mickey has some recent games which would make him appearing in Smash Bros. not totally out of place. Imagine Mario, Mega Man, Sonic and Mickey Mouse fighting eachother! Ofcourse, this could make Sora a Smash Bros. character too.
Epic Mickey can be a quality game again too, with the focus only on the Wii U instead of being developed for Wii and being made by a separate studio for the HD consoles.
The possibilities are big!