I don't think we will ever see a return to "oldschool Final Fantasy". Really oldschool Final Fantasy, like the first 5 games, had a gameplay loop centered around exploration. This started fading away in 6 as the games gradually focusing more and more on constricting you to a linear story. By the time of FFIX, you're play a full blown movie game where you can't go off the rails and do your own thing until several hours into disc 3, at which point you realize that there is nothing to explore and that the combat sucks. FF10 gets rid of any pretense of exploration by cutting out the world map, and FF13 realized that hundreds of random encounters were detrimental to the movie game experience and allowed you to skip them.
So that leaves ATB combat and the aesthetics as the last defining features of the brand to cling to, which have also been eschewed. Gameplay wise, FF13 isn't much different from FF10, but it had futuristic aesthetics that FF didn't want. FF15 ditched the ATB combat so now you have a futuristic action game that is completely unrecgonizeable as a Final Fantasy game. To me, FF16 is in the same boat where it looks too much like Dragon Age or the Witcher or Game of Thrones with DMC button masher combat. It doesn't look FF at all.