343 has confirmed that they want to bring a whole new level of customisation to Halo. Could this include the story as well? I’m not saying that Halo will end up as some sort of Halo/Mass Effect hybrid but perhaps 343 will make the story more about choices more than any other Halo game.
343 might allow players to make simple choices such as which route to take in missions resulting in different enemies and scenery. They might also allow players to choose what to say or do in cut-scenes (personally I hope they don’t for the second point).
Giving a Halo game but a little more customisation in the story will give Halo a more open and free feel which is what many gamers crave.