If you search halo 4 into google news all you seem to find is people saying that halo 5 will be announced at Microsoft’s reveal on the 21st. Some say it will be released in 2013 (Which seems completely far fetched and I hope they invest more time than that into halo 5). It would make more sense for 343 to create a dlc like expansion for halo 4 (like ODST for halo 3) and that way they could use halo 4’s graphics engine to create a new campaign. That way they could deliver a launch title for the new xbox or just release it for the 360. It is just another possibility instead of trying to rush out halo 5.