There is no doubt that many were rather anxious when Halo 4 leaked. Seeing the official reveal trailer only furthered said hesitation, especially when you consider it's a whole new trilogy. Perhaps it's because Halo 3 seemed to round off Master Chief's story so well, regardless of the fact that it ended with a cliffhanger, or maybe it's because Halo: Reach brought so much to the series that it's quite difficult to imagine where to go from there. That is, if you're looking at the Halo series from a strictly multiplayer perspective. Strange as it may seem, Halo has been a series largely defined and directed by its story campaign. If 343 is planning on making any major changes to the series, it may be best to look into how they plan on developing Master Chief as a character.