[wwe2222]

Mostly alot of the larger ideas were worked out...crash on an island that is mysterious, there is some band of others, there will be a hatch, etc...but over the course of writing it, they had to figure out who the main players would be and who would fit into where.

They can still retain the ideas while changing the interactions between the characters.

And yes Jack was supposed to die in the pilot episode, but that was well before they had really cast anyone, so its not like that was a last minute "oh hes good lets keep him"

Also, the actor who played Walt didnt want to be on the show anymore. Niether did Mr. Eko, who even requested they kill him off earlier than planned.

The biggest change the story they made I think is Nikki and Paolo. But luckily they cut the chord on them before they really got invovled.