And on a related note. Why shouldn't they make another Halo game? Having played all of them multiple times and having enjoyed every single one thus far, I think they have a damn good precedent to work on here.
Nothing in Reach or 3 even remotely closed the door on the Halo universe so there is no principled reason why another project is impossible, inconsistent or even undesirable.
Nothing in Reach or 3 even remotely closed the door on the Halo universe so there is no principled reason why another project is impossible, inconsistent or even undesirable.