Kingdom Hearts 3 needs a marvel and star wars world Sora plus Deadpool equals pretty fucking cool. How about Sidious or Apocalypse as heartless. Do you think adamatium could cut the keyblade. Imagine a sword fight between luke and sora because Why not.
Fine then he becomes friends with the powerpack kids and he and luke blow up the death star in the gummi ship. He can summon yoda, leia and kairi become friends sith and Cape heartless types show up because of their whole "blend in" magic.
Well, if you really want Star Wars to be in KH3 Then KH3 has to far of into the future. KH doesn't seem like it wants to use new franchises without having made a movie themselves first.
If you've played KH3D then you know that KH3 isn't far away, there will maximum be one new game before KH3, and so far, only HD-remakes of the older games are in the making, so KH3 is probably way closer then what people think.