I don't like exploring in 12 because it's just a bunch of big empty space
I don't like that everything is a corridor in 13
I realize the result is the same, but the world map in FF4-9 just feels pretty nice, and the corridors in 13 feel pretty awful. A plot progression and a bunch of mountains prevent me from doing anything except Ice Cavern -> Dali -> Lindblum -> Burmecia, but it feels like I have more freedom. Compared to 13 where you're in some corridors and there's no escape. The walls are closing in.
Linearity isn't why the game is bad, though. FFX is almost equally corridor and I love it. The especially melodramatic story and a battle system I can't get into are what do me in.