(Apologies in advance for the bumbling prose.)
Something becoming more apparent is that the flashback structure of Lost is that it allows for inter-generic dual storylines; in the particular case of "House of the Rising Sun," the show got to be a weird marriage melodrama on top of the survivalist suspense default.
Specific to this episode, the ubiquitous present subsumes the Jin/Sun storyline (after it diverged from the generic mood of the episode proper) in the end, inscribing an elliptical/circular trajectory -- see the flower bookending the presentation of Jin's courtship of Sun, and the turbulence (geddit??) in their marriage sandwiched in between; i.e. a pathway of optimism/cynicism (e.g. learning English behind hubby's back!)/optimism -- as though the gravity of the island -- and its tendency towards new beginnings/a return to the zero -- is inescapable.
Yet! Sun is complicit in humbling Jin (via Michael's ax-wielding craziness). Taking into account the show's concerns for second chances and clean slates (the island allowing for the reenactment of Adam and Eve), Sun, as are other characters, is taking the opportunity to forge a new aspect of herself. As it has turned out, being on that plane (for the survivors at least) was a return to an otherwise inaccessible beginning.
Interestingly, Kate's denial of the Adam and Eve scheme complicates matters. The genesis of all humankind started with Adam and Eve, but if Eve is taking herself out of the scenario, then the second genesis can't start -- time is on hold, irrelevant (see also Sun's father's watch, a connection to past lives (and an obvious appeal to time as an issue) laid to waste by the island). And if time is on its way out (time tacitly being one of the most crucial components of modern life), could the rest of civilization/the world (i.e. potential rescuers) be far behind?
And now for the Locke Report: he's still a the resident mystic, but waltzing merrily towards Godhead -- he demands sacrifice (making Charlie trade his smack for the guitar); he reveals his omniscience (Locke's knowledge of Charlie's band indicates a retention of knowledge of his previous life (a deity embodied as a person?). The only other character who can navigate the island as well as Locke (who, seemingly without using his mortal eyes, can see where people's dearest possessions are and what nasty habits they have) is Jack, who found the cave, albeit by accident and hallucination(?).