Even though the Wii got a revision, its not like it was a major one. So i dont see it happening for the Wii U. Not a huge cosmetic one anyway.
How was it not a major one? Nintendo MAJORLY screwed up. They didn't tell companies that they removed the Gamecube support, so whenever you bought products that needed a Wii with Gamecube support, you couldn't know about it until you opened the box.
I was majorly peeved off when I opened up my Wii, and my DDR game mat and game, to find out they weren't compatible. Don't come back with "I should have done my research" because there was no way of me to know. There was nothing on either product descriptions, not even on the box, that I wouldn't be able to use the products together.