How different would the game be? and what would you think Bungie could add that 343 didn't?
The story would have actually been in tune with canon, and thus enjoyable for me and not a piece of crap, and there would actually be a story line hinted at (if it was even going to be a trilogy that is) and loose ends to connect to. Even though CE was not intended to be anything more than a standalone game when it first came out, there were still plenty of loose ends to continue the story off of, like the Forerunners and the fact that there were more Halos out there, or that the Covenant was still out there as well and continuing to wage their genocidal war on humanity. Halo 4 though? Really, what more is there to do? The Derpdact is dead and gone, and the Composer destroyed...what more is there going off of the campaign alone? And one thing we definitely would [i]not[/i] have gotten, as Spartan Ops seems to be hinting for Halo 5, a boring rehash of the [i]first[/i] trilogy where we're fighting what's basically the Covenant all over again.