Early last week I was passed a great website which attempts to shed a little light on the theory behind Lost - and it's a superb read. As a synopsis, Jason Hunter (the author) believes LOST is based on a time loop theory.
The illustration of the time loop theory can be seen here, but for any Lost fan I would strongly advise giving his site a read. It can be found at Losttimelooptheory.com.
His theory is based around time travel, with the island at the centre of a time loop - hence the time loop theory. Ben and Richard play centre stage is all this (as does Locke later on).
It provides insight into the black smoke as a means of 'course correcting' and provides a good explanation as to why people are 'healed' from illness when they are on the island. Here's a time loop theory example - how Locke can walk on the island.
Locke's 'father' pushes him out of a window. He is crippled and cannot walk. This is part of a real world timeline. Ben and Richard travel back in time to 1996 to kill off the Dharma Initiative. Once Ben and Richard start a time loop (the reason the island can't be found) the plane crashes on the island in 2004 - real world time. BUT, because of this second time loop the crash survivors are actually living life in island time - 1996. So when the plane crashes, Locke can walk again because in his orginal timeline, Locke's spine wasn't crushed until around 2002.
Genius. Bring on series 5.