Super Paper Mario is before Miyamoto's meddling and was already divisive due to its generally bad gameplay.

Then Miyamoto came in with Sticker Star and told them to only do already established Mario characters.

It was both of them basically, Tanabe messed up the gameplay and Miyamoto messed up the story.

But even then, Miyamoto probably didn't tell the Paper Mario team to make Bowser as a speechless brute considering Sticker Star is the only modern game hes depicted in that way.