Maps were the number one gripe that most people had about the original Final Fantasy XIII, and with good reason. Every map you encountered (save for the Archlyte Steppe) was like walking through a tunnel, none of the mostly open-ended maps Square put into most previous Final Fantasy's.
Their are multiple reviews that will give a more in-depth analysis of this game, so consider this a basic overview of the game; Minor Spoilers (if you're super picky) Story - I like the story.
I'm a pretty terrible con writer, because it takes a lot to frustrate me in a game; If I was being ~extremely~ nitpicky, and this pretty much only applies to me, I'd say that the fact that you can fly when you use the launch command to attack enemies in the air, and yet are not able to do it...