>>99424432What
>>99424452 said. Remember the storybook scenes in Super Mario Galaxy, the ones that revealed Rosalina's backstory? Most Mario fans thought those were pretty cool--so did Yoshiaki Koizumi, the game's writer and director (and writer of, like, 75% of the classic Zelda series lore concerning the goddesses and the Triforce, etc. Very talented guy).
Unfortunately, Mr. Koizumi went behind Miyamoto's back when he inserted those story scenes in the game. Miyamoto is diametrically opposed to Mario games having any kind of serious subject matter. He's more or less opposed to Mario games having stories in general, as when the Paper Mario team went to him for advice while making Sticker Star Saga, he ordered them to 1) not bring back any previous Paper Mario characters and to mainly fill the cast with generic Goomba and Shyguy characters, and 2) write a shorter, less dramatic script than previous games'.
It was subsequently decided that Paper Mario games going forward would be RPG hybrids at best, so as to distinguish them from the Mario & Luigi series (which was already fairly distinct in its sense of humor). All because Shigeru Miyamoto won't let Mario go. He hasn't director or produced a new Mario game in over a decade, but still, he can't let the younger staff members who grew up on Mario do what they please, because he's stuck on this idea of story being an intrusive, unwanted element in the Mario series, when in reality most people WOULD want to see the characters from across the lore interact with each other from time to time and tell stories, like in a cartoon. Less empty-headed icons that go "Woohoo!" every 10 seconds, more actual character.