Actually the big issue was the massive overhaul they did on the story... originally there no Tidus-clone (Vaan), just Balthier, the charismatic pirate as main character. However, Square thought jap audience wound't like a game with an older protagonist and added the shibuya boy, tidus clone and overall retard vann to the story; that's why he has absolutly no purpose in the plot.It seemed to me, that the script was incomplete, but they've decided to roll with it.
Also, while FFXII regular edition had a skill tree inferior to X, anyone who played FFXII - International Zodiac release will probably agree with me that is the best class system in the series, as it adds 12 classes and 12 different upgrade boards to the game.