They said that Sun and Moon are going to be for the current systems, and why would they release new formes only to release them in the set of games following Sun and Moon?
I personally believe it will either be a Steel - Psychic type, a Steel - Fairy type, or maybe even a Steel - Flying type. Magiana will probably be a Mythical Pokémon, like Diancie, Hoopa, and Volcanion were.