I figured I'd just post this here rather than start a new thread.
M.Night discusses his changes in the movie adaptation:
http://www.ugo.com/movies/changes-to-the-last-airbender Firebending:
Jordan Hoffman: So what are some specific changes?
M. Night Shyamalan: Let’s talk about Firebending. When I first saw the show, I saw that everyone else needed their element around them. You need water to bend water, earth beneath your feet to bend earth and air is all around us. So, the idea of self-manifesting fire was the first thing that popped into my head, in terms of wanting to understand this world. Now, manifesting fire through chi, I thought, was fascinating. So – in our movie – the majority of the benders still need a source. So you need fire nearby, which creates all sorts of wonderful, practical issues.
Jordan Hoffman: This is new. Katara keeps a water bag, but firebenders don’t need that.
M. Night Shyamalan: This is totally new. So the Fire Nation will throw in a fireball not only to create damage, but to ensure that there is a source of fire... It evens the field and sets up a nice hierarchy and, for me, sets up the cataclysmic end of the third act – when the comet comes all the firebenders will be able to produce fire from their chi.
----
Word Pronunciation::
M. Night Shyamalan: Exactly. Now, the other big change is the pronunciation of some of the names. Now this is, for me, because, at the end of the day a South Indian guy directed the movie. It’s a personal thing. So “Aang” is not [like Tang] but “Aang” [like Tong.] It’s “Ang Lee.” So, this is coming from a specific place, from a multicultural appreciation..."Aang" is one. Also, it isn’t “Avatar” like aaah, it is “Avatar” like “Of-Atar.”...We had a linguist come in to discuss all this, by the way, this isn’t just me doing all this...The other changes: “Sokka” [pronounced Sock-Ka] is pronounced “Soh-ka” (“soh” as in “sew”) and Iroh, Uncle Iroh, isn’t “Eye-Row” but “Eer-Row.” Everything else is the same. Iroh comes on the screen and says “My name is Iroh, and you have my word.” And the first thing Shaun Toub, the actor playing him, asked was, “why is it pronounced this way?” because Shaun is Persian. And I’m like, “Dude, I’m on it!” Because this show, this film, is inspired by these cultures. And most directors wouldn’t care, but this is something I’ve been living with my whole life, this is really important to me. But not just the names, the caligraphy, the drapery, the machinery, this all creates a world that is specific and personal and resonant.
----
Humor: Jordan Hoffman: Is one of these other choices paring back the humor?
M. Night Shyamalan: Hopefully there is enough that you will still see characters that you love. But there is so much latitude with an animation that you don’t get with live action. I mean, look at Up, which is fantastic – if you had a little girl pop in and say “You wanna join my club?” it wouldn’t work the same way it works in that movie.