With the Sideways Reality so similar in ways to our accustomed Reality i thought maybe the this is the Big Question of the series. There is all this talk "...this is my destiny" "that was his path" and so on. Maybe destiny means the important things happen but the surrounding events are practicly free.
For example :
- Locke will walk again, maybe this time because of Jack and not the Island ... - Charlie will die doing something for Claire (remember all the things he did while supposed to be dying had claire in common). Though i am interested how they will connect them this time :-) - Jack will go mad over his missing father (remember he never found him until now) - Kate will help Claire give birth and take care of Aaron for a while (if with Jack i'am uncertain, mainly because she was :-) ) - Sun and Jin will part and then try to reunite for a long time. - Sayid will marry Nadia, and she will die, and he goes on a revenge trip. - Jack will read storys to Aaron, maybe as his doctor.
And so on.
I think they will show us that the story would have been basicly the same even if they had not crashed, their conflicts would maybe not have been with the Others, Dharma, Widmore etc. And i think this is also point of view of the writers because you have basicly ideas like this when writing :
"Charlie will try to protect Claire, nearly be killed, rescued by obsessive Jack, then take revenge by killing his attacker."
And then you begin to ask yourself questions like "who is the attacker, what is his motive. How will charlie take revenge..." and so the plot becomes the story, and in the same way destiny becomes life for the Losties.
Oh, and my final prediction is "The Island is SUPPOSED to SINK"