I kinda like the idea that if Daisy got her own game it'd be like Diddy Kong Racing, a multiplayer game with a primarily original cast and world not from the Mario (Land) universe. Maybe Tatanga or Totomesu could be there, but I think Daisy's competitive, hyperactive personality would be really fun to extend with a new friend and enemy group for her, as well as a new world that revolves primarily around competition and sports.
but im not complaining, it will finally come out of beta