First off, apologies to anyone who has written anything similar. I would hate to be accused of stealing.
This is just a simple thought that I may expand upon later, but for now would like some comments on.
I believe Darlton will attempt to appease both groups of fans, the ones that believe whatever happened happened and alt timeline fans.
When "the incident" occurred it created two separate realities/universes. One where the losties have changed nothing and one where they reset the timeline. Season six will play out by flashing back and forth between allowing us to see both timelines. I have further thoughts on the story specifics but will save that for another post.
So from the incident two realities have arisen and the main arc of season six will be to converge the seperate realities together and make them one.
Hence, Everything That Rises Must Converge.