#2 Neymar

A long-term injury might have meant that Neymar has not been talked about as much this season, but the World Cup is just the stage to make a return. Despite not playing for almost half of the season, he has managed to score 27 goals for the French champions.
Like Isco, Neymar is a force to be reckoned with at the international team and its playing style revolves around him - like it should. Also, Neymar will be more rested and fresh than the other players on this list, and we can only expect more and more goals out of him.
With Gabriel Jesus and Willian and Coutinho joining him in the attack, Neymar has more than enough quality to assist him. The World Cup could just be the difference between a Ballon d'Or this season for the Brazilian or not.
If Neymar wins the Golden Boot, and helps Brazil win the trophy, he could make a surprise entry into the list of possible candidates and finally break free from the shadows of Messi and Ronaldo, just as he has always wanted.