Looking back over the episode and thinking it over, the episode in and of itself wasn't tht bad of an episode. Just watching it alone, it has B+ level of storytelling meaning it's a fairly decent episode.
+ Emotional atmosphere, writing and dialogue and music
+ Tense moments
- "In The Nick of Time" Hook's change
- Deflated "hype" and suspension
- "vial of magic"
A decent episode, but if you rmemeber that it's a piece of a larger puzzle, that's where it falls flat. The biggest fail in Once is always the payoff, but in this case it's just the episode having scenes unearned.
Emma and family scenes were unearned. Emma and Snow scenes were unearned, mostly. It was lovely and had all the "feels" but the show didn't earn it. Snow has been so far away from Emma, you'd think she was trying to avoid her.
Zelena's banishment was unearned. The only ones who would like it is if they hated Zelena or loved Regina. However, it wasn't earned. The previous episode and the season demonstrated a chance at humanity within Zelena, but that was dropped like a bad habit and she was quickly banished.
Rumple and Belle's scene was unearned. Belle was to go see the world and take a breather beyond the angst, but she quickly came back. While touching, it wasn't earned after Belle's whole self-respect speech.
Robert Carlyle used subtlety in the episode which was cool to look back at and see when Rumple returned to the dark side. However, this show hasn't earned his level of subtlety in his acting. This show is Evil Queen's level of subtlety which is none at all. They mentioned the Underworld. Sent beasts from the Underworld. Saw dead loved Ones from the Underworld. Remembered time spent in the Underworld. Did I mention they mentioned the Underworld?
Hook's quick turn was unearned in this short arc of his. Just how Regina's quick change in the episode "Mother", this flashback that calls itself into the plot was unearned. These things should come up earlier. Someone should have told Regina that something else may be standing in her way of happiness. Hook should have mentioned early on that he was trying to be the man Emma deserved, a noble one or something close to that. Same with Rumple.
Rumple's quick turn done with subtle acting was unearned. He should have felt his lust for power as he was afraid. He should have shown more signs, perhaps even a dream sequence. It was a nice parallel to the season 1 finale to have Regina and Emma to come into his shop for a sword to stop evil and for him to betray them, but..........nope, not at all deserved. It was a cool parallel for Belle to return just like the season 1 finale, but it wasn't earned. This is the third time there is an evil plan behind Belle's back.
So much was unearned character-wise and scene by scene. This brings the episode down to what was truly earned which was a D+.
Then if you take off what you may for individual greivances like shipping (or character) angst and hate-fuel, reused storytelling elements, or even being used to the usual Once end (where the characters solely used for this arc leave and get closure). But whatever it is, the episode on its merits of storytelling as a part of the entire series was shallow. As a season arc finale, it was below average. As an episode, it was decent at best.