I doubt we'll see another MMO prior to seeing another single entry in the series. XIV isnt as old as it seems, and while some things aren't as fresh, it's still a very modern game in many ways. And I wouldn't use FFVII as a reference for another single installment. Remember, the remake of VII has been in the works since XV wasbeing "reworked" on.

I do however think they will take time to try and really flesh out the next game. Both XIII and XV are umm some of the more controversial, and both went to two different extremes in the way of storytelling. People have their own preferences, but I feel we need another narrative like we had in FFX; it had both linear and free roaming gameplay.