Ok, I guess this is why you take a breath instead of just flooding the forum with posts.

Just to post post some speculation, obviously first thought was the image was of John in Forerunner armor, but seeing the ONI symbol on the chest, as well as its similarity to SIV armor has me hoping were gonna see a dual story, similar to H2, where we play as a MC and possibly a SIV. I think it is significant 343i chose to place the new character above the MC.