I remember reading reviews like "So many twists in the game to keep you entertained. There is only 3 twists.
1. Vossler's betrayal - I was a bit shocked but not that shocked. They pulled this one way too early to get that much of a suprise out of me. They probably should have held this one off a bit and let him turn against you near the end.
2. Balthier reveals his past - Wasn't really that shocked, more pissed off as I thought it ruined his sky pirate gimmick and after this scene, he didn't seem the same as he was at the beginning, more dull I think.
3. Balthier's father - They never really made a big deal out of this except Vayne mentioning it afterwards, that was it.
None of these really kept me interested in the story that's for sure.
I personally thought there was more. Like... I dunno... the twin thing? Granted, it was towards the beginning, but it had a lot of people fooled when they first learned about the game.
I'm biased since I'm a Balthier fan - I liked the reveal of fact, but I would have loved to "see" it rather than "hear" it. I think the "dullness" came from the fact that he realized he was becoming his father - to a point, and was trying to deal with it. Kinda like Luke Skywalker syndrome.