Ronaldo is not in a position to decide what criteria that the FIFA should use for deciding the Ballon DO'r winner, rather the FIFA body, There shouldn't be a need for this if a player from the champions league winner meets their criteria to winning the Ballon d’Or, I doubt if FIFA won't consider the player the deserved honor. Champions league is a superior competition no doubt the players performance their and wining the title shouldn't be the only criteria to judge who will be the Ballon d'Or winner.
But he is in the position, he has won Ballon d'Ors and he knows the corruption that exists there, everyone knows that Rodri didn't deserve the Ballon d'Or yet he won it, so what do you think that is? Corruption? Yes... then sometimes the criteria they take is just convenience or bias and if this year they come out again with the award for a player who doesn't deserve it, then this competition will not have the credibility it had before.