Martinez, GGG, are career 160. Canelo is career 154. Kovalev is still to unproven to know much about him. I dont wanna give him the nod against Cal based on potential because regardless of how people feel about Calzaghe, he is proven.
Calzaghe by decision over all of them. Kovalev is the only one with the size and style to pose a threat, really.