There is nothing to worry about. Tabata mention in an interview that he is sure another director will use ATB in Final Fantasy again, he considered it for FFXV but decided not to for the style of which FFXV is. That actually have me quite excited! We could be getting Action RPG and Tradition Turn Based RPG's. I love both types, I just get disappointed when I see people bash one over the other, especially turn based since it's basically what founded JRPG's.