I love talking about this stuff.<br/><br/>Personally, I like the idea of Aang aging after his iceberg was "cracked" open.  Perhaps the Avatar state was enough to keep him alive, but the ice kept him ageless?   I don't know.<br/><br/>As for spirits: there's plenty of evidence to suggest that the spirit world is complicated, bizarre, and confusing.  It's easy enough to believe that most spirits wouldn't be aware of what was happening on the mortal world as long as it didn't cause a lot of damage to nature or the spirit world.  The slaying of the Moon spirit would likely alter all of that, if that happened in this timeline.  Without Aang the Northern Water tribe would've fallen in the series.  However, without Aang there Iroh and Zuko would likely not have been there and the Admiral would've been victorious by simply kidnapping the spirit and not permanently harming it.  With both water tribes conquered all power would've been focused on the Earth kingdom.<br/><br/>Also, if Aang never woke, Sokka would never have fixed the Inventor's air balloon which means the Fire Nation wouldn't have an air fleet and Osai wouldn't have the means to implement his "scorched earth" tactic.  With Azula conquering Omashu and Ba Sing Se and no Avatar to marshal a resistance there again wouldn't be a need for the scorched earth tactic.  Also, as cunning as Azula is, and with her poisoning Osai shortly after his coronation, I don't think there'd be an attack against nature or the spirit world.  Which would likely leave the spirits largely unaware of what happened.<br/><br/>For me, the biggest hurdle to Aang joining Azula is that the Fire Nation destroyed the Air Nomads.  They didn't jut conquer them, but they committed genocide simply because the Avatar was going to emerge as one of them.  Granted it wasn't Azula who did it, but it was her family and it wouldn't take much investigating to figure out that the war lasted 100 years, or that the Southern Water tribe was all but wiped out.  In fact, the remains of the Southern Water tribe are very likely the first things Aang might see.  If not that, than possibly an Air Temple.<br/><br/>Getting Aang on Azula's side should take more than simply out-of-control hormones.