After seeing the last Spartan Ops episode(Janus Key), concept art released by 343, and viewing the teaser trailer that was released at E3 2013. What are some ideas on which direction the story is going to take?
ONI becoming more and more insidious.
Earth government being Human Supremists and looking to consolidate their status in the universe, rather than assuming the Mantle.
The Chief perhaps feeling incomplete with Cortana. ONI trying to “retire” him.
Chief going lone wolf and searching for answers in the universe and perhaps hooking up with Arbiter when the UNSC turns on him.
Flood coming back to test Humanity’s worthiness…
Of course, all of this is conjecture 
I would have to agree! I keep thinking that the flood is coming back. I also think that something has to do with Cortana being taken by the librarian in Halo 4. Also, I’m waiting to here what the “absolute Record” is…