I have to agree; the new armor does look a little weird on the RvB characters (the armor looks too serious on a bunch of comedic soldiers). But other then that, I thought the video was really funny (especially Sarge). I now wonder what's RoosterTeeth gonna do with Halo 4 engine when it comes out (especially Monty and team).
From what I understood from the GameInformer article on Halo 4, those will be the basic level "training" helmets. Armor modification is synonymous with Halo multiplayer, so there isn't anything to worry about.