Really? I'd say voice acting and overuse of cutscenes. Back on the PS1, but PS2 was good as well, the games were text based capturing the imagination your mind creates while reading. That's why the book is always better than the movie, why people on forums exaggerate the emotions in your posts, why you develop unique tones and voices to characters you read about.
I'd bet there are three highlights of dissapointment in FF XIII that all FF fans sharred. The moment you exit Cacoon to the outside world and figure out it's still linear, when you are on the airship and start text dialogue conversations to never experience that again, and when you find the robot sidequest just to realize it's the only one outside of hunting.
I have never been trolled by a game so hard.
EDIT: Just to make this clear I'm not leaving out NES and SNES, it's just PS1 started the 3D versions of FF and since then something was lost as they pushed towards higher end 3D graphics.
Before the PS3 everyone was nice to me :(
