That's what Yglesias wants to do:
My family took me to the Met a bunch when I was a kid. I’ve been to pretty much all of Western Europe’s super-obvious famous museums. And it’s just clear that Donatello doesn’t have the star power of the other three.
My suggestion as a replacement turtle would be Titian. He doesn’t quite have the blockbuster appeal of the other three, but no one does, and I think he comes closest. I also think he chronologically matches the other better. I suppose the counterargument would be that he’s Venetian and the others are Florentine, but it’s all Italy to the kids.
My biggest problem with the Ninja Turtles was that Shredder never, ever, EVER won. Even as a kid, I always had a soft spot for the underdog, even if they were the bad guy. Why can't they let the bad guy win sometimes? He'll get his ass kicked in the next episode anyway, so it doesn't actually mean anything. I mean, even Tom got some good shots in at the rat Jerry, so why can't Shredder ever come out on top?