We can still expect a lot grom GEN 6. Zygarde is going to be a very complex pokemon and besides, we don't have a clue about Xerneas or Yveltal when it comes to historic facts. Furthermore, both games have diferente endings. In X Lysandre probably obtained eternal life like AZ but in Y he is most likely dead or at least deformed or something. Xerneas and Yveltal's powers are completely oposites and I think it is a first time in pokemon game series that influences na ending or a future game.