My thoughts. They could sell the new halo with the campaign, but give a code to download the Muliplayer like 3 or 4 months later. Why? Because we all want (or most of us) a real and classic Halo. Meanwhile those 3 or 4 months, trying a Beta that could come randomly in any copy of the game, or give it to personalities of the game.
Sorry if my English isn't the best. I'm latin american. (And I also like to cross the border )