Has there ever been a game that introduced a new form for a past-generation Pokemon? Excluding Megas.

I'm just having a hard time understanding why they'd reveal forms for Zygarde yet release those forms in a new generation, if that is indeed what they're doing.

Since they've shown that they don't mind making games within a generation obsolete (with the introduction of ORAS-exclusive megas) it wouldn't surprise me if they'd do the same with species. So maybe they will actually do a 6.5. Muhh patterns have all been broken in the past few years starting with B2W2, so who really knows anymore?

Another thing I thought of. Why would they reveal both Volcanion and Magiana in the same movie, yet have only one available in the games? Has that ever happened? Are they just going to distribute Volcanion and pretend Magiana doesn't exist? Distribute Volcanion before gen 7 is released, then have us transfer Volcanion to gen 7 to get Magiana like they did with the shiny beasts and Zoroark? I wish they'd just fucking tell us the next game.