I have noticed that Bryke have let their fear of social disaproval keep them from presentiong death.Mostly,I blame sociaty for being as stubborn as to subtract death,an important and natural part of life from the equation.And for what,to keep a few tears from being shed and to keep little kids innocent and clueless all their lives?These people need to learn that their kids will have to learn about death sooner or later.I mean,even some G movies have death in them.Dont get me wrong,this is a great series,it just has a few flaws.I am not attempting to flame or rant,just share my words with others.

Nick doesn't have that much of a problem with death...but things in avatar involved killing...

Actually, it's Nick that didn't allow it, but as you saw from The Southern Raiders and afterwards, more death refference have been allowed, showing that they can go there.

Also, it was confirmed that Lake Laogai (the episode where Jet dies) and The Western AirTemple had to be changed due to the deaths, so Bryke indeed had the intention of killing as clear as possible.

Lastly, Aang's final move was made by them a long time before they got to actually make the series, ever since Nick made the series, they already knew how Aang would finish him.