With regard to FFXIII, I heard several common complaints about the gameplay—linearity, no backtracking, lack of character customization, no overworld map—but all these really boil down to a single perceived problem: a lack of choice.
There's just one small problem with this criticism, however. Except for the two MMO-Final Fantasy games, Final Fantasy has never been about choice.
To start with, Final Fantasies—and JRPGs for that matter—are incredibly linear. In none do you have the ability to go where you want and do what you want (until the very end of the game). Instead you are herded from town to town, event to event, and dungeon to dungeon as the plot demands.
The overworld map itself is just as much a linear corridor as anything in FFXIII. Each area of the world map generally has a single entrance (where you come from) and a single exit (where you are going). Everything in the middle is just space filled with monsters and lower resolution graphics than you would find in your average dungeon—and of course the occasional town.
Unlocking the airship simply allows you to quickly move to any point in the world map corridor—giving the illusion of freedom, nothing more. The ability to backtrack itself serves little to no purpose other than giving you a second chance to gather any items you missed on your first pass—though they are likely useless by the time you can go back for them.
Even side quests don't really add choice to how you play the game. In most of the Final Fantasies, side quests don't unlock until right before the end—and generally do little more than pad your play time before finishing the game (I'm looking at you, FFX lightning bolt dodging).
The customization found in leveling up the characters is likewise an illusion. While leveling up, Final Fantasy characters—especially those in X and XIII—are very different from one another. But by the end of the game, each character tends to be able to perform any role in the party.
Now, while there are exceptions to many of my statements above, they are generally true for Final Fantasy as a whole. So while there may be many valid reasons for disliking Final Fantasy XIII, lack of choice isn't one of them. Just as you don't blame a snake for being a snake, you shouldn't blame Final Fantasy for being a Final Fantasy.
In other words, Final Fantasy games are just the same as they've always been, with the majority of changes being not in gameplay but in graphics and story. The problem is that gaming has evolved in many ways besides graphics and story—making Final Fantasy look stuck in the past. Whether "being stuck in the past" is a bad thing or not is completely up to each individual gamer.
Of course, if all goes as planned with Lightning Returns: Final Fantasy XIII, those longing for more freedom in Final Fantasy may just get that choice-filled world they've been longing for.