In many ways, the Shyamalan version got this right. The opening of Katara practicing her bending and dropping it on an unsuspecting Sokka is a rather nice one to follow. Not as presented, of course, but the idea's still there.
Aang's discovery is something prime for revision, and the cartoon provides a very interesting opportunity for character drama as well as an exciting way to bring Aáng into the story; the derelict ship. It serves very little purpose in Aáng and Katara's section of the story when Zuko can just as easily be informed of the Avatar's existence through the light of his breaking out. But, it provides an interesting set-piece for developement of Sokka and Katara.
This ship, like Katara says, carries a great deal of painful memories for the whole tribe. As such, it might be a good way to provide character drama right off. Say, a few skeletons that spark something within Katara.
The Legend of Aang : The Youth of the Water Tribe
EXT. SOUTHERN WATER TRIBE – DAY
A plain of water moves gently as we pan across it. We land on a girl, KATARA, practicing a Tai Chi-like form by the side of a lake. She concentrates hard, but is unable to move the water.
KATARA once again extends her arms in an attempt to move the water in the lake. She grits her teeth, but once again holds her arm out.
A small blob of water comes out of the ocean, and KATARA grins. She forms it into a stream and moves it around herself in an intricate formation.
What are you doing?
She gasps and whips around, taking the water stream with her. A loud grunt is heard off-screen. She then clutches her arms to her side as she looks toward the source of the noise.
A seventeen-year-old boy, SOKKA, stands perfectly still, eyes clamped shut and water dripping from his face. He eventually opens his and gives a loud groan.
KATARA rushes to SOKKA’S aid, a rag in her hand.
I’m so sorry.
What’s wrong with you?
Look, it was an accident.
Not that! I’ve been calling you for the last half-hour.
But, on the subject of your practice-
What were you calling me for?
I’ve finally found them. Tigerseal tracks.
And the last four times won’t be remembered…?
This is different. This is real.
KATARA nods mockingly.
Look, do you want to come, or what?
As long as I don’t have to pull out another fishhook…
Hey! That doesn’t happen three times, Katara.
KATARA and SOKKA trek across their home, following the tracks carefully as they go, passing, rivers, glaciers, ice plains, and various common sights for them.
SOKKA eventually reaches the end of the tracks, and is shocked to see that they abruptly stop, with no lead to a pack. He squats down and attempts to read them.
That’s impossible! How can they just end?
KATARA looks around for signs of an animal pack around, but stops cold as she stares at something off-screen.
Well, sorry for dragging you all the way out here for nothing…
SOKKA tilts his head up when there is no answer.
He sees her staring off and gets up to see what she’s staring at, and his eyes nearly bulge when he sees it.
A FIRE NATION ship, shrouded in ice and surrounded by a glacier, is seen in the distance away from them. SOKKA starts toward it, a manic grin on his face.
Where are you going?
SOKKA turns back around to face her.
That thing’s got to be chock full of supplies. I’m going to go check it out.
We can’t go there! What if it’s still-?
Look at it. We’ll be fine.
He starts off back toward the ship.
EXT. FIRE NATION DERELICT - DAY
SOKKA arrives at the entrance of the ship, and admires it for a second. He looks behind him to see KATARA pursuing him.
He starts to climb up the ice to the ship. He enters an open porthole before checking behind him. KATARA looks up at the ship in a daze.
KATARA looks up to him and shakes her head.
SOKKA sighs and crawls out of the entrance a bit.
Look, you’ll be safer in here with me than you will be alone out here. Come on!
Are you sure?
I promised to keep you safe, didn’t I?
KATARA reluctantly begins to climb up the side of the ship. She nearly slips, but SOKKA grabs her hand and pulls her up the rest of the way.
INT. FIRE NATION DERELICT – DAY
SOKKA and KATARA enter the ship’s dark hallways, and start down one corridor. SOKKA grips KATARA’s hand the whole way.
The two look through many rooms and hallways, seeing many different sights, including skeletons and different pieces of weaponry.
They come to one room, and SOKKA chooses to survey around them while KATARA looks in the room. She screams softly and pushes up against the wall, hyperventilating.
SOKKA puts his hands on her shoulders as he looks in the room.
Several skeletons and instruments of torture line the walls and floor.
SOKKA turns back to KATARA.
Katara, calm down.
I saw her… She’s in there…
No, she’s not. They’re all flamers. I promise you.
SOKKA grips her hand. KATARA starts breathing normally again, and swallows.
Let’s get out of here.
No. I’m fine. Let’s see what we can find.
INT. FIRE NATION DERELICT – DAY
SOKKA walks into a room and tries to read the labels of some boxes on there, but it is too dark for him to see the labels. He pulls a small pack of matches out of his pocket and takes one out. It takes several strikes, but he finally manages to light it. He then sticks it to a torch, and almost unwittingly drops the match on the floor.
The match falls to the floor, accidentally igniting an old fuse. SOKKA leans in closer with his torch to read the printing on the crates.
INTERCUT: The fuse burns, ever so slowly making its way to the boxes.
SOKKA eventually wipes the ice off of one of the crates, and his eyes bug out as he sees what they say. He then turns to see the fuse, making its way to the boxes.
SOKKA rushes out of the room, dashing through the hallway, and runs into KATARA, who’s holding a couple of bags.
Oh! Look what I found-
That’s nice. Let’s get outta here.
I’ll tell you later. Just, hurry!
He grabs KATARA’s arm and leads her away, causing her to drop the bags. The fuse nearly finds its mark.
EXT. FIRE NATION DERELICT – DAY
SOKKA rushes with KATARA out of the SHIP.
He rushes her over to a snow mound and pushes her behind it, before joining her. He peaks over the edge.
The fire finally meets its target; a load of gunpowder.
EXT. ICE PLAIN – DAY
The ship suddenly bursts in a spectacular explosion, with debris being scattered and the very hulk of the ship being torn to shreds.
KATARA and SOKKA duck behind the snow mound to avoid flying debris.
EXT. ZUKO’S SHIP – MAIN DECK – DAY
IROH is taking a sip of tea. Upon hearing the rumbling of the explosion in the distance, he hesitates for a moment. He disregards it and resumes his tea.
EXT. ICE PLAIN – DAY
The explosions begin to die down, and some of the larger debris begins to sink down into the hole left by the ship’s absence. Various bits of metal no bigger than a foot are scattered around the large pool of water.
SOKKA and KATARA peak over their snow mound and see the ship’s absence. The both lean on their elbows as KATARA gives a suspicious and angry glance in SOKKA’s direction. SOKKA then leaps over the ice-mound to go look into the hole. KATARA groans and follows him.
SOKKA looks into the water, seeing if there’s anything to salvage. KATARA arrives behind him. He then squints his eyes as he leans forward.
What did you do?
Sssh… Look at that. What is that?