Which is the character you expected the most from, but dissapointed you for awful execution?

Not much, but Asuna should be the main character of the show. It started as a girl that could fend for herself, then it became generic tsundere #305, then damsel in distress #1000, then it was unactive, then it returned to sort of badass. And all of this because Reki Kawahara wanted to make a male power fantasy. Well, considering he started to write SAO when he was a teenager...