Just throwing it out there. Does everyone remember halo 3: recon (halo 3: odst). Names change, so the people angry about the name just hold your horses. This is very early stage stuff. The point of the trailer was to show that the next halo will have a new engine, old halo art style, Master Chief, and a halo.
Yeah but Halo 3 Recon was originally just a DLC that got converted into Halo 3 ODST. I think this games title is a for sure thing.