I believe Cesar revealed a large piece of Lost theory when he was in Ben's office. He found a diagram in a folder that represented multiple events tied together via Real Time, Real Space and Imaginary Time, Imaginary Space. It also included Silent Interval along with proportional formulas written between Events. Then, what happened to Cesar??? He was killed almost immediately AFTER that reveal. What other purpose did Cesar serve??? None that I can think of. I have spent quite a bit of time making sense of event probability and how it ties in with time travel as well as other Lost events. I would provide more in-depth detail, but I have diagrams and such that I cannot post on here - so I may make a website and post the link instead ;)
Basically the theory can substantiate alternate timeline meshing with the correct final timeline or some derivative thereof because it is Event based. For example - if Event A = the bomb exploding in 1977 does that lead to Event B of Flight 815 landing safely in LAX or does it lead to Event C the bomb kills everyone in that area (or island) or does it lead to Event D which could be Desmond not causing the 815 crash because the Hatch no longer exists hence no 108 minute entry.
Further you can use it to explain Desmond's 'mind time travel' as he was bouncing to different events in seemingly different timelines.
I would actually be shocked if Cesar's reveal is not used as part of the end game to Lost. How great is that to reveal something by a 'new' character and kill him off so we dismiss it as unimportant.
Feel free to post comments - there is quite a bit more to discuss :D Can't wait for Season 6 - but it will be a sad Season - dunno what I am gonna do :(