Here is an article from OXM talking about Halo 4 info:
and here is a cool analysis of it that I found:
"We’ll start with the obvious. Halo 4 picks up immediately after Halo 3’s Legendary Ending where we see the aft of the Dawn tumbling towards the Legendary Planet.
“…it’ll follow on from the events of Halo 3 when you complete it on Legendary. The “Legendary Planet” glimpsed after Master Chief goes into hibernation aboard the ruptured Forward Unto Dawn is the same structure you see at the close of the Halo 4 Awakening trailer.”
We’re practically guaranteed that John will be the only Spartan in Halo 4, 343i have noted “fan displeasure” over the fact that John played no part in Reach. Generally, I think the sales speak for themselves; the games with John in have sold better than those without, obviously ODST was an expansion and Wars was an RTS but ultimately this has taught 343i that the path to further widespread success is sticking to the core foundation of the series.
“Yes, he’s still the hero… aware of fan displeasure over the Chief’s absence in Bungie’s final Halo game, Microsoft and 343 are focussing squarely on John 117 this time.”
And, as has been said before, John has ‘changed’ in some capacity.
“…there’s evidence to the effect that Chief has undergone a psychological shift, with 343 staff hinting at “different behaviours”. It’s possible all that time in cryo-sleep has done nasty things to John’s brainbox. It’s also possible the years of Grunt-popping and Elite-dicing are beginning to drag on his subconscious. Don’t forget - Spartan training is hell on earth, and the Chief hasn’t exactly had it easy since he graduated.”
This is what I like to hear. John is suffering from a degree of psychological trauma after fighting almost non-stop for decades, it’s all finally weighing down upon him, much like the information Cortana absorbed from Halo began to weigh down on her in First Strike when she began to process it all. This certainly looks like interesting territory we’ll be moving into in terms of how John will develop as a character.
But we’re assured that there’s not going to be any drastic personality changes to rival Twilight in terms of angsty teen-slitwristery.
“We’re not expecting a “dark” Chief or anything similarly contrived, mind. The man’s blank-tablet impassivity is key to Halo. The last thing anybody wants him doing is manifesting hidden depths.”
But, following this…
“Cortana, on the other hand…”
Let’s talk about Cortana for a minute. She’s been through a lot since Halo CE:
Absorbed all the information from Installation 04’s Control Room, found it difficult to process all of it and it started to weigh her down.
Went through a rough spot in First Strike where John started to note that she was acting differently, her tone of voice towards him and actions seemed a little off.
Made hundreds of copies of herself that all turned rampant within seconds attempting to combat a ‘Covenant’ AI aboard the Unyielding Hierophant.
Went through a very traumatic time with the Gravemind when she was left behind on High Charity, as we saw in Human Weakness (penned by the indomitably grey Karen Traviss) where she began to really question her role in events and built up a hatred for Halsey. We can account this for the melancholy stage of rampancy, a state she seemingly escaped when she was rescued by John.
Returned to her state of melancholy aboard the Dawn whilst John was in cryo. She lamented the loss of so many lives in the Human-Covenant war (and the wars before that) and discovered that it was human instinct to want to fight.
So, what do 343i say about what’s next for Cortana?
“Well, she’s an AI. AIs enter a state of Rampancy after seven years on the go - symptoms include delusions of grandeur, hatred of constraints, hatred of one’s maker - and Cortana’s lived a more… interesting life than most. She seems fairly compos mentis in the Awakening trailer, but let’s not forget that she spent much of Halo 3 being cyber-tortured by the Flood Gravemind, and that she’s absorbed massive chunks of Covenant and Forerunner data. That’s an incredibly potent mixture, and the effects will be interesting to watch. She may push through to the hypothetical fourth stage of Rampancy, ‘metastability’, becoming a true person. Or she may “turn evil”, as the kids put it.”