After all this time I think it's time for a reboot of the Mario franchise. I'll give some ideas:
The Mushroom Kingdom was completely destroyed after a nuclear war. In this age, a man named Mario must rescue his fiancee Peach from his old friend (and now rival) Luigi. To do so he'll use his secret technique, the Plumber shin Ken, that allow him to destroy the turtle shell of his opponent, often resulting in a violent and gruesome death.
This one is for the japanese market, to recover the favor of the otaku japanese hardcore gamers:
Shitty and Boring Porn Game Visual Novel:
You are Mario, the new transfer student in Mushroom High School. Your objetive in the game is to have sex win Peach's heart before the graduation party. Mario the Main Character will be able to befriend other people like Luigi the Loser, Bowser the Bully, Pikachu the Pet, Wario the Wacky, Birdo the Bisexual and Peter the Parker, the guest artist. Mario should be happy careful because other girls like Daisy or Rosalina will try to fuck him draw his attention, preventing him from fulfilling his naughty goals.
After beating the game a new mode will be unlocked, Girl Mode, where you can play as any of the girls you have completed her route in the normal game. In this mode your objetive is to enslave charm as many male students as possible to become the School Queen.