ok i know im really late to this but to truly clarify all of this, 343 changed the look of the armour and the overall game because they wanted to show that they are capable of making the same creative decisions bungie would have made. Thats why there is barely any of the classic score remade to fit a sequel, and also why for some god-aweful reason they brought a forunner into the story who dies from a single grenade... during a cutscene... almost like he wasnt even in the game... anyway theres my 2 cents hope it makes more sense now.
and its that that makes me said. at one point in time (before I played half life) chief was my hero part of it was his nice green armor which was my favorite cooler. I care less about halo now but still I fell said when I see his armor turn gray and halo turn into what ever it was I saw in 4 and at e3 with halo on xbox 1.