I am going to go on a whim here. But since Kishi did say he was a big fan of Akira Toriyama (Dragon Ball). And Seeing how Naruto was drawn as older. maybe he plans to do the same thing Akira Toriyama do. Make movies as sequels after the manga ends.
Tho this theory might not work, since the "Last Naruto Movie".
Maybe Kishi is planning to end his manga, with some things unresolved (romance etc etc). And just make a movie an epilogue.
Just guessing here!
Edit:
Official designs!
Sakura looks gorgeous!
