Another big problem with the Shyamalan version.
Zuko is first seen in a disjointing cutaway to his ship, in which he has only one line; "Uncle, look!" It's not a good introduction to our supposed anti-hero protagonist, especially seeing how much of an impact he will have in later films.
That being said, the cartoon's version isn't exactly the best role-model either. Zuko was characterized as nearly a Malfoy-type in his first appearance, and wouldn't exactly be taken seriously if characterized the same in the film. Not to mention, his motivation definetly needs an earlier introduction.
So, what to do?
Have his introduction be a nightmare he has of his banishment, then segueing into a scene where he trains aboard the ship, which also provides introduction to Iroh (another character who just sort of "appears" in the film.
The Legend of Aang : A Prince in Exile
INT. FIRE NATION – DUEL STAGE – DAY
A figure obscured by fire stands over a scrawny child, kneeling on the floor.
You have spoken out of turn, Prince Zuko.
The child, ZUKO, stares at his father standing above him, terrified for himself.
I know… I’m sorry, father. I didn’t mean to.
OZAI (V.O.) (CONT’D)
You must now fight for yourself, my son. To regain your honor.
ZUKO gets to his feet and attempts to hold his fists up.
You planned to kill innocent people. I had to say something! I meant you no disrespect.
Then figure walks toward him, and ZUKO lets his hands down.
I can’t fight you. There must be another way.
The figure walks toward him, at first not saying anything.
Please… I don’t want to fight you, father.
ZUKO stares at his father, his eyes welling up.
If you will not fight, then you will learn. And this shall be your lesson.
OZAI casts fire at the screen as a sharp cry is heard.
INT. ZUKO’S QUARTERS – MORNING
ZUKO, who is now several years older, awakens after a particularly bad dream. As he turns over, we see that a large burn occupies most of his face.
EXT. FIRE NATION SHIP – TRAINING DECK – DAY
ZUKO faces several soldiers as well as a few machines. One lunges at him and he deflects it, while also blasting fire at another soldier. He leaps up from his spot to avoid another attack.
ZUKO widens his eyes as he ducks another fire blast. He chops another soldier and throws him into a mat, before turning to another. He stops another hand from hitting him and kicks him down.
Another soldier gets up and chases him to another fighting mat. The two share a long exchange of moves, until the soldier catches ZUKO off balance and ZUKO goes tumbling down.
IROH comes rushing to ZUKO’s aid, but ZUKO gets up on his own and brushes himself off, before motioning the victor away. He turns to IROH.
That was better. You’re still working from the brawn, however. Not the breath. And anger is your sole drive. Serenity provides control, but anger lets one lose a grip on it.
What do you propose I do about it?
Perhaps you should take up meditation. I find it relaxes the mind in times of unrest.
ZUKO looks to IROH.
Take, half an hour. Then we’ll begin again.