From http://nintendoenthu...cters-in-smash/
In a recent interview with Xenoblade Chronicles X director Tetsuya Takahashi, the executive revealed that Monolith Soft is already working on its next game, even though XCX has yet to release in North America.
Moreover, Takahashi also answered a question about have characters from XCX in Super Smash Bros. To that question, Mr. Takahashi simply said to “ask Sakurai” about their inclusion.
I’m not entirely sure, but you could always ask Mr. Sakurai about that.
December seems so far away for X. Interested to see what they do next, couple of years away until we learn anymore I am sure.