wow edmasterofchaos yeeesh where to begin
1) the thing about bloodlines here is not the same as naruto BUT it has been stated before that his unique bloodline allowed him(zuko) restore the honor of the
fire nation because he has the blood of BOTH sozin(ozai's father and a force of chaos) and Roku( a force of order) showing the battle within him yes he was very capable of
teaching firebending but it truly is his bloodline and the talk within the cell with iroh(the avatar and the fire lord which wow i am watching now) that prompted me to say he is smilar to the avatar
2) well in the series finale he was a sub battle over all(main battle of course avatar vs fire lord) so it wasn't that he wasn;'t useful it was that he just wasn;'t the focus that's all
3) first off jeong jeong was not of the blood line if you know anything about royalty overall blood can only rule with certain exception sitautions
4) about the blue fire. the blue fire comes from being centered and calm without shame after the firebending masters zuko shared that with azula just he wasn't nuts
5) there were a few times in the series where Aang came out exhausted even though yes he was enraged during those times but being enraged is enough to give a person a serious
headache but not drain that much energy and yes rage can drain energy to a certain extent but still not enough to render a person completely exhausted and asleep.