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>...Could...Could they have hinted about this and we just never noticed?
I'ts obvious that they did. They were developing XY and BW2 at the same time. The main team working on XY while Takao Unno worked on BW2 to give the main team time and prepare the ground. Just read the credits.
Colress basically concluded that Pokémon needed the trainer's friendship to reach new secret powers, which is why we have Pokémon Amie and Mega Evolutions now.