Very interesting thoughts here. However, the one thing about this show is that they leave signs of what could lead in the story. Some of the signs they have left for us are simple.
I have said this for some time now and I am hoping to see it come true in this season. Here goes:
Ursa is still alive. She has been hidden for some time. In fact, I think she will come out in the painted lady episode. Think about this for a moment. She left Zuko with the thought, "Everything I have done has been to protect you." So this leads to believe that she has set things up for him. Now I would not put it past her that she spoke with Iroh prior to her leaving. Based on the information given to us in Zuko Alone, we have enough information to surmise that she is in hiding right now and that Iroh was very close to Zuko. Look how Zuko defended Iroh from his letter.
Speaking of his letter, remember the part where Azula says, "If Uncle doesn't make it back from war, then dad would be next in line to be Fire Lord, wouldn't he?" This line makes me think that there was a plot to ensure Ozai to be FL. The reason why I say that is because suddenly Iroh loses his son. Hmmm. That seems convenient. Suddenly Ozai is before Azulon pleading his case for him to reconsider Iroh as the next FL.
Woah!!!! That just makes a ton of sense right now. Now what if the plans were overheard by Ursa and she knew that the war was wrong at this point because of the incident with Iroh's son? So she planned to maintain Zuko as the next heir the throne so he could stop the war. What better person to do the job then Iroh.
Dun Dun Dun...
Guess what, now Iroh stays by Zuko's side to guide him since his mother left. Iroh techinically has become a father to Zuko. Think about this line from Iroh in the Guru episode, "No, I'm thankful because you decided to share this special day with me. (puts a hand on Zuko's arm) It means more than you know. (Zuko gives him a warm hug, to his surprise)" Now his guidance has been carefully plotted up to the point when he says, "You are not the man you used to be, Zuko. You are stronger and wiser and freer than you have ever been. And now you have come to the crossroads of your destiny. It's time for you to choose. It's time for you to choose good!"
So here is my completed theory. Zuko is not going to die because that would leave no one to rule the FN. Zuko is far too important of a character to kill off. He really holds the hopes of the end of the war and the future of the FN in his hands. Ozai might die or be imprisoned, Azula will also be imprisoned, and Zuko will befriend Aang. You are probably saying, "Yeah right! Zuko friends with Aang. Ha ha ha." Well guess what, the writers kind of led to the that fact in the Blue Spirit episode. Aang says, "You know what the worst part about being born over a hundred years ago is? I miss all the friends I used to hang out with. Before the war started (cut to Aang still looking down at the ground), I used to always my friend Kuzan. The two of us, we'd get in and out of so much trouble together. He was one of the best friends I ever had (he turns to face Zuko) and he was from the Fire Nation, just like you. (Cut back to Zuko still looking at Aang.) If we knew each other back then (cut back to Aang), do you think we could have been friends too?"