So now we know who was in the coffin. But the big issue, that I have not seen anyone talk about, is what happened to the island. The orientation video spoke of the vault being used to make the rabbit time travel, and the implication is that whatever is behind the vault powers this effect in some fashion. So did the island move in space? Or just time?
Another question I have is about Sun. What is her agenda? Is she out to get Widmore or Ben? I guess it depends on who is the other person, besides her father, she blames for Jin's death.
What isn't make a lot of sense to me is if John Locke is the chosen man, why does Jack and pals leaving the island make everything on the island go bad? If I were to get all geeky about it I guess I would ask, why does the island want/need Jack? And if it really wants/needs him so badly, then why didn't it tell him so before he left?
Lastly, is the resurrected Christian Shepherd the devil? Or some form of evil? He claims to speak on Jacob's behalf, but does he? More importantly, what has he done to Claire? How did he convince Claire to leave her child behind? I'm guessing that what goes wrong on the island after Jack leaves has something to do with this specter of Christian Shepherd.