Just read Berserk's latest chapter, and wow.
This more or less addresses what we all could see plainly, pointing out the true difference between Griffith and Guts and explaining what Skull Knight meant all those chapters back.
Griffith is and has always been a slave to fate. Every choice he made was spelled out to him to led to the Eclipse. Even in the missing Chapter 83, where he meets the Idea of Evil, he is told explicitly that mankind as a whole has no choice in the matter, and neither has he.
But then there's Guts. A man born in defiance of a normal destiny, born in death and yet he lived, and has continued living against all odds. Fans have long since idolized this representation of him that he embodies the free will of mankind, that he isn't special. Some people are upset that this new chapter seems to go against this, despite the fact that this story development was apparently in Miura's intentions all along.
I believe it doesn't contradict them, but rather proves them right. In a world where free will has been thought to not exist, here we have a man that said world does not understand. A man who defies the fate laid before him, a man who can choose. It's his choices that have led him to where he is now, and it's his choices that have changed the destiny of all those around him. Farnese, Serpico, Schierke, Casca, even Jill from Lost Children.
He may be trapped in a world who's course is set, but his isn't. This is what sets him apart. He is the truest representation of Humanity and Free will, in a world where such things are play toys for greater forces beyond human understanding.
To reference what Skull Knight said when he first met Guts: He is the fish that lept out of the water, the fish that is aware of the water. He cannot change how the river flows, but he can choose where he swims. And unlike Griffith, when presented with this inexorable fact, he chooses to fight instead of submitting.