There should be another halo game that tells the story of the Arbiter (Halo 3). It should have the story like in the books where he was Thel Vadam'ee. Where he would do secret missions for the Prophets. It should also have a free roam where you are a certain rank of a ship and try to rank up and control the ship. Just pointing that out they need to fill in the blanks that should be like halo reach it filled in the blanks for Halo.