Very disappointing news... I had hoped the whole Hayter not reprising his role thing was just a big joke. Casting Sutherland is a mistake. This has more to do with maintaining consistency within the MGS world. This will break the immersion and make the new games feel disjointed. Why change it at this point when the voice of Snake/Big Boss is well defined and works so well? If there was a good reason I would be more understanding, but at this point it just seems like the answer is: "A change was needed". The sense of familiarity and empathy for Snake/Big Boss is lost now since the new voice is not relatable to the player (in the context of the MGS world). In other words, the heart of the character has been removed.
Not necessarily. The headline is misleading, we only know that Sutherland is voicing Big Boss. If these games follow their logical continuity, eventually we will be revising the events of the original Metal Gear where Solid Snake and Big Boss are both central characters. Establishing a new voice for Big Boss now could simply be laying the groundwork for MGSVI or whatever it ends up being. Having Hayter screaming back and forth at himself would be significantly worse.
That's a good point. If this turns out to be the case then it will work out well in the end. We may even see Snake and Big Boss confront each other at the end of MGSV.