OK, so everyone has their own theories and everything about what the hell is going to happen in season 6 and whether the bomb went off etc etc and here is what I think, its a pretty basic theory I think...
RIGHT, so we all believed that Flight Oceanic 816 was brought to the island as a result of Desmond taking time off button duty to kill that dick Kelvin =: the electromagnetic force somehow pulling the plane towards the island, BUT what if this is just coincidence. Up until the Season 5 finale I thought yeah fair enough that might be why the plane crashed but seeing Jacob apparently bringing that ship to the island (presumably the black rock) and seeing him appear in most of the main character's lives pre-island suggests that HE brought them there for a reason unknown.
THEREFORE, if we now combine this with Daniel Faraday's theory that things CAN be changed in the past and that detonating that Hydrogen Bomb would mean they never came to the island, perhaps he is wrong. PERHAPS they would still come to the island just at that key plot changing moment in Season One when Locke discovered the hatch, things would be different. If this is the case, maybe the whole storyline would shift back to Season One where most of the characters were alive and the story would continue but without the hatch. The twist might be that the main characters transported from the past (Jack, Sawyer, Kate etc...) dont entirely forget everything that happened and spend their whole time reliving events and trying to stop disasters from happening (ie Boones death). Miles would go back to living his normal life, Juliet would perhaps be back with the others.
I know its crazy but it might be good, plus we get to see people like Charlie again. :)