One thing I really like about Lost is that it has a designed end. The creators have always claimed that, and they followed through by vowing to wrap the story up (if not every lose end I suppose) at the end of season six. Due to the nature of production, however, a lot of story details have been developed on the move. Issues as tangential to the story as the real life careers and plans of cast, end up impacting details of the story.
So my idea, not that it'd ever be done, is that it would be great if a final version of lost inluded going back and making some of the afterthoughts, forethought. For example, go back to the birth of Aaron, and add a rustle in the forest, or even show a shadowy shot of Sawyer there in the woods. Such shots could be subtle, like easter eggs, or they could be overt. When future generation of viewers (i.e. anyone that hasn't watched it yet) see this, they can find the easter eggs, and perhaps pore over the enigmatic tells. After all, if the audience sees sawyer there (obviously Kate and Claire still wouldn't) they would assume it was the present day Sawyer, not a future version.
I'm curious if anyone can think of any other patchwork that would make a final edition of Lost more potent using time travel savvy tie ins and enigmatic foreshadowing. Cheers.