The Final Fantasy series gets a bad wrap about its problem feeling too linear over the past couple of games. Japanese RPGs (J-RPGs) in general get this label attached to them. A big problem is that these games shifted how the player explores the world from a “make your own path“-style of traversing their worlds to a “connect the dots“-style – going from town A to town B and so on until you get to the end of the game.
But, I guess what I want to discuss is that Final Fantasy games and JRPGs as a whole have never really been open-ended and non-linear but older JRPGs just did a better job at hiding their linearity from the player. It all depends on the scale of which you explore each area before moving to the next.