The producers of Lost, Damon Lindelof and Carlton Cuse, said that they will not tell the history of the Libby's character on the show, because they considered this history finished. So... why the big twist left in the end of the episode "Dave" with Libby on the Santa Rosa if they don't gonna tell us her history? I think they need to have a little more respect with the fans and honor they promises to the Libby's backstory.

Here wath they said on a recent interview:

"Obviously as the story moves forward we'll be answering questions at a faster rate. But some stories -- like Libby's -- we feel are pretty much finished."

AND here what they promissed last year:

"She'll be in enough of the show for us to fill in the missing pieces of her story," says Cuse. "We could not be more pleased. Cynthia is a smart and engaging actor, and [executive producer] Damon [Lindelof] and I have some very cool parts of her story left to tell."