Wow! First of all, what an amazing episode. Terrific development and great balance of plot and action. Anyway, I noticed that this episode contained quite a few revolutionary moments in the World of Avatar, in other words events that happened that I would not expect or that have not happened before.
The first and most obvious event is when Eska gives Bolin a betrothal necklace. Generally the boy gives the girl a necklace requesting her hand in marriage, but also this custom is typically only practiced between members of the Northern Water Tribe, and not only is Bolin not from the Northern Water Tribe, but he is not from either Water Tribe.
Another norm that seemed to be broken in this episode was the use of firebending as a defense against waterbending. What!? (This occurs right as Korra rescues her father and everyone is escaping onto Varrick's yacht) This completely contradicts the fundamentals of each of these bending arts, and it does not appear that strange at first, since similar situation occured before where waterbending was used to extinguish the aggressive attacks of firebending, but when you look at how each element is being used it looks fairly unusual. Even though we do not see the firebending defense as having flowing motions to counter the attack, like we usually see when waterbending is used to defend against firebending (notable by Katara in Siege of the North, Part I), we do see the fire used similar to how Aang uses water to void the three infernos that Ozai fires at him, where the person being attacked responds by targeting the attack, rather than specifically defending himself/herself from it.
One last norm that was broken that I caught right away, and it honestly kind of bugged me (hence why this section is a little more colloquial), was Korra's reaction to the entire process of her parents being arrested and her father then be sentence to life in prison. So her parents are arrested, by Unalaq's doing may i remind you, and she just says everything should be okay because Unalaq says so. Are you kdding me, that's not the Korra I know (and love). Unalaq should have been sent flying fifty feet in the air by a single stomp of the foot, only to return to a whirlwind of fire before he even opened his mouth. Instead Korra trusts him and then proceeded to make light of the situation in the courtroom when her father was condemned to life in prison, and she goes and thanks Unalaq for lessening her father's sentence! There is no way this is how Korra would normally react, so how can it be explained. Korra's reaction to the arresting was definitely not because she was still mad at her father, because they had previously made-up and even though Korra is rash, she definitely does not hold grudges, plus her mother was arrested too. I conclude by saying that at this point, I believe the only logical reason for Korra's mellow reactions to these events is to emphasize the extent to which Unalaq had manipulated her.