I think it's definitely good for Nintendo to flex their creative muscle and crank out some things they truly enjoy making, being in the creative business they're in pushing boundaries is a good thing. At the same time they're a business that provides a product at a certain level of quality and style their fans expect. They essentially work for the fans so ultimately the focus should be more what the fans are looking for.
Games like NSMB simply should be made at times, as they help keep their business running so they can be around to crank out the weirder stuff in the first place. And hell, the "creative freedom" angle vs "business side" don't always have to be mutually exclusive anyway. If a game is of enough quality and appeals to enough people, but ends can be achieved simultaneously.
"We hold these truths to be self-evident - All men and women created by the, go-you know - you know the thing!" - Joe Biden
