Take a good look at this picture. Notice anything strange? It states that Sutherland is Snake. Not Naked Snake or Big Boss; just Snake.
Now throughout all the Metal Gear games, Solid and Naked were never referred to as Solid Snake(for the most part) or Naked Snake, but just snake. However, any character introduction in the games stated their full code name. Here, Sutherland is playing the role of Snake, but it isn't clarified if it is Big Boss/Naked Snake. Watch the video again and notice they never say Big Boss, just simply Snake.
I think Hayter is still the voice of Big Boss, but a new Snake will be introduced in MGSV. That Snake is voiced by Sutherland.
In short, Kojima is trying to ruse the fanbase once again.