Mario is over-saturated that said ... if there was to be another Mario spin-off that turned into a blockbuster IP, the often speculated about "Mario Paintball" would probably be it. That said I'm happy they went with it as a new IP.
I still think they could very easily have Mario DLC/Amiibo features for this game where you can unlock a Mario FLUDD mode or have Mario characters in the game as a side-option.