Yeah, in the weeks before the film came out, I acctually sorta imagined what scenes each song would be used for. Personally, I always saw "Flow like water" as the scene where Yue gives her life to revive the moon spirit, because it seemed dramatic, but poetic and tragic at the same time.
I imagined a live action version of the actual blue spirit escape from the show as going with the track of the same name. Turns out the actual thing was far less dynamic then the track implied it would be.
Also, I know other people thought the same thing, but during the airbender suite and the blue spirit, we hear this sor tof pompus marching theme, and I thought that just screamed fire nation theme. I could see Zhao struting down corridors with his troops or Vast swaths of fire nation soldiers menecingly marching into an earth kingdom town.
And when I heard "Journey to the northern water tribe" I got this sense of a sort of Lord of the Rings esq traveling through epic landscapes thing. Once again, I was dissapointed with only the montage of them "starting the rebelion".
I really think the score was implemented poorly and that it rarely was used at it's fullest potential. Even if you've seen the film, i'd still recomend buying the soundtrack. Just imagine your own movie when you listen to it.