A couple of thoughts on the episode....we now know,or do we,from Naomi and Locke's father that Michael and Walt have not "escaped" since both said there were no survivors.So,where are they?
The Others wanted Locke because he is special,but so is Walt.Why would they have let him go?
Did you notice the size of the camp? How did they carry that much equipment?Certainly not the way we saw them pack up.
Does the column have any relationship to the four toed statue?Are they related to the "older place" Ben referenced to Locke?
Then there are the mysteries of the ship and helo not "seeing" the islands or noticing the interference on the radios, radars,etc.
One of the better epi's since season 1-answered questions but introduced more unknowns.It's fun to watch again.