Its completely impossible to determine the best player in the world because different players play different roles and are in different systems with different cultures. Some players will shine in some situations and slump in others, perhaps a player might pop off and shine under a regimented structure like DRX but would struggle playing for a more casual org. Or vice versa, not every player is given the same opportunities and environments to thrive which is why we cant determine who the best is. You could make the argument that the best player would be one who is consistently good under completely different teams and different roles.