Iroh (Shaun Toub) and Zuko (Dev Patel). Image from Avatar The last Airbender Online
2) Shyamalan's past success with child actors is not replicated here. The lead Noah Ringer puts up a valiant effort to convey the director's habitual gravitas, but lacks the charisma to pull it off. It doesn't help that he has to deliver some very atrocious dialogue. Most of the other cast members sleepwalk through their lines, barely expressing any emotion other than furrowing their collective brows. Dev Patel comes off the best as the conflicted antagonist Prince Zuko. But none of the cast has really been given that much to work with.
3) Given that the original series main draw was its mystically enhanced hand-to-hand combat, this happens to be the movie's biggest let-down for this fighting arts geek. The bending fails at pretty much every level. Hollywood directors are usually unable to mimic the balletic wire-fu of Hong Kong cinema, and Shyamalan is no exception: His staging of the fight sequences is pedestrian at best, and the fight choreography in itself is brief and perfunctory. There's not a single memorable duel between any two characters in this movie when there should have been at least half a dozen. As for the cast themselves: I'm used to untrained actors moving stiffly when trying to perform martial arts moves, but it looks even more egregious here. I understand that the twelve year old Noah Ringer is trained in taekwondo, which imbues him with a lot of physical dexterity. However, his tai chi chuan imitation is mediocre, and not significantly better than the efforts of co-star Nicola Peltz. Most of the supporting cast could have benefited with some more formal training, if only to learn how to maintain a proper stance. As for the special effects used to depict the elemental bending, they're generally disconnected from the actors physical movements. It often looks as if they're waving their arms and feet frantically for a few seconds before an element shoots out from behind them. It's terribly unconvincing, and lacks the clever variety found in the TV series.
4) Regarding the racebending controversy that has taken up a lot of public attention - Changing the cast to satisfy the critics would not have fixed the structural flaws of the story. However, there were two instances were I was more conscious of the racial makeup of the cast: Early, when I couldn't help noticing how everyone in the Southern Water Tribe was of Asian extraction except for Katara's and Sokka's family. And later during the climatic battle between the relatively light-skinned citizens of the Northern Water Tribe, and the swarthier Fire Nation soldiers. This is counterbalanced to some degree by the fact that the two most interesting characters are Fire Nation citizens Zuko and his uncle Iroh, played by Shaun Toub, who is underutilized in his role. The casting may not be the worst thing about this movie. But it's a terrible distraction that compounds the movie's many faults.
5) The TV series was not historically accurate in the conventional sense. But in its world-building, it cohered around certain details. The stylistic breakdown of the varieties of quan-fa was one. Or the way its architecture and fashions formed a close analog to real world Asian cultures. The movie deviates from the original in small ways that would be irritating to the series fans. For example, Chinese characters are replaced with an invented script that looks like someone's bad imitation of Chinese. Or Shyamalan's changing the pronunciation of certain words to make them sound more Indian, which only pushes the film further away from the imaginary milieu of the series just to satisfy his personal vanity.
6) When I first heard that Avatar: The Last Airbender was being made into a movie, I suspected that this would be just another poorly executed adaptation that I could afford to skip. The irony is that the casting controversy and calls to boycott the movie piqued enough of my interest that I wanted to see just how big of a train wreck it would turn out to be. Well, the movie isn't just bad. It's so bad, it lacks even the usual technical competence displayed by Shyamalan. It's as if Paramount went out of its way to ruin its very own franchise. So I should have stuck with my initial gut reaction. Another, more familiar, irony is that if the movie earns enough from its international releases, it could make back its costs despite being almost universally eviscerated by the critics.
More on Avatar Racebending