Sakurai would most definitely have included Mai if the CERO rating boards in Japan weren’t so strict. (They are similar to the ESRB in the US.) Here is [a good article translated by SourceGaming](https://www.sourcegaming.info/2015/09/18/cero-and-palutenas-censorship/) on a similar matter concerning Palutena in *Smash 4* that reveals Sakurai’s personal opinion on CERO. So it’s not an issue with Sakurai or Nintendo – it’s literally just CERO.