If anyone's sad that the chief's story is not continued, then pretend that his story continued in Marathon. At least he didn't die and break a billion of fanboy's hearts. He's out there somewhere in space, cryo-genically frozen after saving humanity and the galaxy, destroying the flood and covenant, and liberating humans and elites all around the universe.
I say that moving to an ODST solider was a very smart move by Bungie that I'm thrilled about.