I had an idea that in Halo 4 the helmets and visor could change your HUD. A lot of people (Me included) dont think armour should affect gameplay however if it only effected YOUR HUD layout and colour it wouldnt really alter gameplay at all. There could be an option to choose whether or not it changes as some people may prefer the default colour/layout.
An example would be http://images.wikia.com/halo/images/7/76/H3_MkVI_HUD.jpg.
If you look at the image, the semi-transparent lines could change depending on the visor shape of the helmet you are wearing, and the ammo colour and shields ect could change colour depending on what Visor colour you have equipt.
