I don't quite follow how and when Sarah & Ben meet and grow some kind of romantic interest in one another.
Also, I thought that Ben was somewhat able to leave the island and come back, before the explosion at Des' hatch took place. If that's the case, why bother with time-traveling to find yourself one Jack Shepperd to cure some future-cancer. As opposed to checking into a clinic in Florida or somewhere in Switzerland..
I know not many would agree with me on this, but I never get the Sarah-Juliette resemblance thing. I mean, I get the references & hints from 3rd season and this last episode reminds that yes, but the two don't look alike to me physically..