You have all given me something to think about!
I think that there is something to do with father issues somewhere in there. Locke's dad pushed him out of a window and generally treated him badly, Jack keeps seeing Christian although he is dead, Christian is also Claire's dad, Kate killed her step father, Miles didn't know his dad until he got to the Island, Charles Widmore is Daniel's dad (although I don't think that Daniel knew), Ben's father resented him, Sawyer's dad killed his mother and then himself...that's all I can think of at the moment.
As an aside, wasn't it nice to see Rose and Bernard, albeit briefly!