There are two moans here. One is low pitch and the other is high pitch. In my mind, there are no doubts, this is Hayter. Sutherland has a higher pitch than Hayter. This is no Sutherland here. My initial assumption was he was returning back as Solid Snake but Big Boss? I don't know what is going on in MGS 5 anymore.
I was a bit concerned for a while because i thought what if Sutherland is just a ruse and David Hayter will voice Big Boss in the final game but then i thought about the TPP 30 minutes gameplay demo where Sutherland says "Spit it out" and tells the horse to stop and stuff like that, so i still think Big Boss = Sutherland, Solid Snake = Hayter.
Another thing that almost locked it for me was again that quote from Quinton Flynn the voice of Raiden. Now keep in mind Flynn is a very good friend of Hayter, he calls him David and even prank called him at some event sometime ago.
He said on a podcast just a few days ago this:
more information has been revealed to me, i didn't understand it in the beginning. So then i was perplexed and later it was explained to me, no he (Sutherland) is replacing Big Boss, David will still be Snake.
He also says this:
but you know as well as i do there must be more to the story that none of us really know.
You can check it out here: https://www.youtube.com/watch?v=d373xZ6Yz_k#t=28m
This convinced me more than anything else. Sure some doubters would say yes Hayter is still Snake but that doesn't mean he will be in MGSV. But i personally take it as a hint.
I almost want to be team A just to be in that epic picture.Almost
