All "Exclusive Moves" Pikachu or any special Pikachu would get from the past are now available through in-game Move Tutors (Doubt Gamefreak would bother with this since "making game very hard, please understand".) under specific circumstances:
>Contest Moves can be learned if you beat a contest category with Pikachu
>Hat Moves can be learned if you fulfill a certain criteria in game that matches the hat of that Region
>etc.
What changes?