He was never a warrior to begin with. He always wanted to be a sky pirate, and he was pretty obnoxious and immature. Balthier or Basch would have been a better knight for Cosmos's Army. Even though Balthier was a pirate, he still became a hero. Basch served in Princess Ashe's army, so he was always a warrior. While playing Duodecim, I found that Vann's storyline was very odd. Other than teasing Light every now and then, he didn't do much except fight Galbranth. He also seemed like a secondary character in Terra's storyline.
