1. I think (I never saw A:tLA) that the Fire Nation was portrayed as evil, thus they killed characters' parents. LoK is not like that.
2. A. Do dead Avatars "become one with the Force", or is there a body? If there is a body, it can be resurrected. B. I doubt that they would portray Amon as a great danger to Benders, only to later say that he is not as much of a threat. A bit anti-climactic, I think. Also, before I watched the episode, I had wondered if Amon were a Bender. I still think that he may be one. If he were, it would be quite a plot twist.
Note: Did anyone notice that the main character's eye colours are the same as their Element colors? (Blue=Water, Green=Earth, Red-Brown=Fire)