Here's a couple of old quotes by Shigeru Miyamoto on Mario 128: "I believe that with this game you'll be able to feel the 'newness' that was missing from Mario Sunshine. As for Mario Sunshine, it would be very easy to take the Sunshine engine and create a sequel to that but really right now what we're focussing on is what really is fun, and how can we take that and find a way to make it accessible to a much broader audience."
BTW, I had a class with a Miyamoto this week. It was a five day creative curriculm planning class and her name was Sue Miyamoto. I don't know if there is any relation, but it was still kind of neat to see Miyamoto on the sign-in sheets.