It's been over ten years since the first Halo game was released, and even longer since we first laid eyes on the Master Chief. A lot has changed since then.
Like, ten years of combat has literally sucked all the colour out of him.
More seriously, I'm slowly coming around to appreciate his armour in Halo 4. When you see it in action, the decrease in plating makes it seem more practical than the BMX padding he was wearing in Combat Evolved.
Not that I'd know. My first-hand experience battling aliens in the future is somewhat limited, so I'm only guessing as to how useful all that stuff really is.
Master chiefs evolution [BigBossGamer69 @ Reddit]