The Mega Evolution specials and the whole Zygarde/Alain/Flare arc in the XY&Z season is the closest the Pokémon Anime has ever been to a great quality production with compelling and amazing story telling.
Unfortunately, with SM appearing to be school life comedy skits ft. Ash and the pokeymans, I don't think we'll be seeing more of that for some time. Well, let's wait and see.
By the way, when is the OST coming out? I want to hear the actual full version of this:
https://www.youtube.com/watch?v=VKNnNMHUtho 