I will respond with another question:
What is this show about? Is it the story of a mysterious island? Is it about the age-old struggle between MiB and Jacob? Or is it the survivors of a plane crash?
For me, even though we've been introduced to a lot of new characters and new mysteries over the last 6 years, the story of LOST is, first and foremost, about the survivors of Oceanic Flight 815. I want to see what happens to them
. That isn't to say that the Lost universe doesn't have more stories to tell, but this story
is about the characters that we met in Season 1...and Desmond.
I would love it, however, if the creators someday do a series of "Lost Tales" (pun intended), that explore some of the Island's greater mysteries.