Cast the Expert: Noah Ringer (Aang) was cast more for his martial arts experience (he got a black belt in Taekwondo at the age of 10) than his decent acting ability; in fact he had to take acting lessons before shooting started because he'd never acted in front of a greenscreen before. Ironically however he did seem to have the personality that would fit Aang (energetic, fun loving, etc).
Creator Killer: Shyamalan's career wasn'texactlyspotless before this film, but it looks to be the final nail in the coffin. For his next film, Devil, he was neither writer nor director and his name actually drew jeers from audiences when it appeared in trailers. His next directorial effort, After Earth, did not mention him in any promotional material and also avoided showing his name until the ending credits rolled.
Dawson Casting: Jackson Rathbone (24) as Sokka (15-16). Although that is the only example, as the others are played by actors of a closer age. Rathbone apparently had a good screen test with Peltz and very much looked like her older brother. He looks awkward playing opposite Dev Patel, who is six years younger despite playing a character one year his senior. Suki would like to have a word with you.
Disowned Adaptation: Avatar co-creators Michael DiMartino and Bryan Konietzko seem to share their fanbase's distaste for the film, having said in interviews that it distorted their vision of Avatar and have even advised people, including members of the original cast not to watch it.
The first draft of the movie included all twenty episodes of the series, adding up to a whopping seven hours. Instead, the movie was cut down to barely two hours, and Paramount also had another half hour of film cut from theatrical release because they wanted to convert it into 3-D as quickly as possible.
Before things turned stillborn, Shyamalan planned to counter the 'Racebending' complaints in the sequel by casting Toph with an Asian actress. Unfortunately the wording seems to imply that the overall Unfortunate Implications would have remained.
"...the Earth Kingdom is all Asian so Toph will have to be [Asian]."