Chapter 1: The Awakening
There's an interesting recurring theme in Avatar of separation and reunion between parents and children. There's Sokka and Katara's separation from their father; Sokka's reunion with Hakoda near the end of season 2; Katara's anger at her father in this episode; the death of their mother and Katara's search for closure; the death of Iroh's son and how it affects his relationship with Zuko; the disappearance of Zuko's mother; Zuko's banishment and longing for his father's approval; Zuko's tense reunion with his father in this episode; Zuko's choice to leave his father in DoBS; Toph's separation from her parents and (unresolved) desire to see them again, which comes up in a couple of episodes; Zuko's break-up and reunion with Iroh in season 2; Zuko's betrayal of Iroh in CoD and separation from him through most of season 3; Zuko's reunion with Iroh in part 2 of the finale; Ozai's abandonment of Azula in the finale, adding to her post-Boiling Rock distress; Azula's estrangement from Ursa and her vision of her mother in the mirror. Did I miss any?
I like the gender balance in this. In many epic adventure stories, the focus of any parent-child angst is between fathers and sons; Avatar spreads it around more and manages to hit every combination.
I also find especially interesting the parallel between three of the reunion scenes: Sokka's reunion with Hakoda, Zuko's audience with Ozai in this episode, and Zuko's later reunion with Iroh. All are preceded by a scene of the boy walking toward where he knows his father/father-figure is with a look of anxiety.
Chapter 4: Sokka's Master
Piandao is awesome. If you miss him, check out this fanfic.
Chapter 5: The Beach
This episode really makes me wonder about Azula's fate. When she finds Zuko drowning in his memories at the beach house she seems genuinely concerned about him. She would share many of those memories, too. Is there any hope for her?
In defense of this episode—as I said to attaining recently—it's not right to dismiss this episode as "filler" when it does so much to flesh out the characters and to develop Zuko's character arc in particular. We have to see him lingering in confusion for a few episodes so as to make his later actions seem believable.