Modding Halo 4 Weapons

So going back and playing Halo 4 I find one of my big problems is the weapons. Either the look and sounds of some of the existing or the lack of weapons I think should have been in the game. To entertain my curiosity if you could add 2 weapons to the Halo 4 campaign from any other Halo game what would be your choices? As example I would probably add the classic battle rifle and the blood of Suban.