This is why I think Aang died!
I have noticed the that "Previously on Avatar" blurbs before each episode??are answered in the episode. In this one, Roku was warning Aang about dying in the avatar state. He had an exit wound on his back, meaning that Azula's bolt of lightening went right through him. Katara's water brought life back to him!
Can you see the irony? If Katara had used that water on Zuko's scar, who evetually betrayed his Uncle and fought against them, she would have had none left to keep Aang alive.
This show is fantastic! I was almost foaming at the mouth! The fight scenes were incredible!!