Deifying is the basis of the holiday. You're just as likely to get rid of the deifying of Sinterklaas and Piet as you are getting rid of religion, or getting rid of the custom of giving gifts during the winter holiday season.
It's not that I don't agree with what you're saying, it's that changing the character is the only realistic change I can see happening in the next 50 years or so. And that might be a optimistic assessment.
You see, what you are battling in Piet is not a thing created for entertainment of adults as with the minstrel shows known to Americans. What Piet does is specifically spreading joy and excitement to children. And when it comes to seeing the joy in the faces of their children, rationality of parents and grandparents most often goes out the window. "Think about the children" is a hard mentality to fight in the best of circumstances. In this case, I'm afraid it will be a losing battle for a long time to come.