Why does Master Chief's armour change drastically from Halo 3 to Halo 4?

Why does Master Chief's armor change drastically from Halo 3 to Halo 4? 

I’m going to start off by saying that Master Chief’s armour change is not 100% because of a change in Bungie’s art directive. Sure we’ve seen some desaturation of the Mjölnir Spartan armour as Halo progresses and advances graphically, but I’m focusing on the obvious huge change between Halo 3 and Halo 4. Chief was in Cryo-sleep for his whole 4 years, seven months and 10 days “holiday break” to escape the events of Halo 3, so he could’ve hardly just got up for a bit to change. Anyway why would another full Spartan suit casually be on the Forward Unto Dawn? Chief is the last Spartan, so it’s clear the armour he’s wearing is the same as in Halo 3. So why does it look different, and is there a cannon reason?

Halo novel ‘Glasslands’ gives us the first clue. In the book (which is Bungie confirmed and cannon) that the Mjölnir mark 7 power armour had Nano-machines capable of repairing and altering the suit. However Chief sports the Mark 6 in Halo 3, so that’s not the straight up answer. It is related though, so keep that in mind. On the other hand, Frank O’ Conner; the franchise development director for 343 Studios directly stated that the Chief’s armour had been repaired by Nano-bots. This proves that Halo 4’s armour is exactly the same as in Halo 4, just an upgraded design. So how did that happen if his suit doesn’t have the self-repair bots built in?

Halo.Bungie’s archives contain a useful source for this theory. In a news bulletin for September 5^th, community manager Jessica Angelshay stated that the chief’s armour (in Halo 4) was “Very fancy, very custom, very unique Cortana special armour”. This leads us to believe that Cortana had some play in the changes to the Mjölnir mark 6, after all she did just kinda sit there and kill time for like 4 years. Having direct control to the Cryo-pod that that Chief was housed in, she could’ve made changes to the suit to prep him for future battles when she wakes him. But that still doesn’t explain everything, since there aren’t Nano-bots just floating about on the Forward Unto Dawn, where did the Nano-machines come from?

Every Halo player has driven a Warthog at some point, probably flipping it off a cliff or succumbing to the terrible steering AI. Did you know that they get their fuel from using Nano-machines to convert water sources into Hydrogen fuel? And where are the Warthogs stored? That’s right, on the big ol’ spaceship that Chief was sleeping on. We know they’re on board somewhere as Chief finds some later to drive, and an AI who has full control over the ship could easily re-purpose them to fix the armour. I think it’s fairly safe to say at this point that Chiefs new look is a nice little gift from Cortana herself. Well she had to have some hobby in all that time.  

So why did the large gash on the right hand side of the breastplate remain? Well we never see a full shot of Chief’s armour until he’s crashed on Requiem, the co-op mode doesn’t count as it is not canon. It could be argued that the gash occurred as a result of Chief’s fall, though that it’s on the exact same side as the mark in Halo 3 is a little suspicious… But the final end-game is a fact from the essential visual guide to Halo. A small note literally states that the Chief’s armour was upgraded by Cortana, the design based on an old iteration of the mark 4. Another good point towards this is the one of the first lines chief says as he’s leaving the pod; “You’ve been busy”, which could be seen as an off-hand compliment to Cortana’s work. In conclusion, I would say all facts point towards the armour from Halo 4 being an upgraded version of set seen in Halo 3, and not a whole new model.

Sources:
Halo Bulletin - 09.05.2012
http://halo.bungie.org/halobulletins/65

The Science Behind Halo:
https://www.youtube.com/watch?v=Qjswo...