Let me ask you one thing: what reason did you have to save Cocoon?
It was filled with NPCs that talked shit about l'Cies and Pulse, and, somehow, you were supposed to want to save it it. You spent your whole time running away from a place that wanted you dead. Can you genuinely say you wanted to save Cocoon? For what reason, other than it's pretty? OMG it makes sense in the context of the story, but the story is shit and they could have written a different one that allowed you all sorts of freedoms, instead they wrote a steaming pile of crap that resulted in a 25-hour dramafest and tunnel vision until you get to the "good part" with still more drama. Because you develop little connection to the world, unless you love the characters you will feel dead about the end. Unless you love the characters, you will not really want to save Cocoon, except to end the game.
The nature of a world is characterized by the civilization that lives on it. NPCs give substance to a world by presenting varying aspects of its culture and their particular concerns, and fleshes out history and details without having to resort to a menu option. Is it that you like having a bunch of text to look at for convenience instead of interaction with people? Or are you the kind of person that just likes navel-gazing and focusing only on your characters and not caring two shits about the world?