Friendly reminder that there is no Battle Frontier in ORAS because Gamefreak knows exactly that nobody would buy Pokémon Z (or whatever the next game or games will be called) afterwards. So it is pretty much confirmed that the Battle Frontier will be in the next game(s).

They had to take out the best feature from ORAS to make sure that everyone will buy the next games, too. Thats why there are so many hints in ORAS. Simple marketing.