He's really just a generic sort of character, and that's enough to fill the role of the on-screen indicator as to the players location. Platforming games need something for the player to control, so Mario may as well be a ball, or a fish with legs, or a wise-cracking dinosaur teen with sunglasses. Point is, it isn't important. Story and character depth aren't of much concern here. I don't think we honestly need a reason to go through these games, other than enjoyment. Enjoy the challenge, enjoy the music, enjoy the visuals. Mario is a placeholder that, due to the early success of his games, is quite recognizable at this point. It makes more sense for Nintendo to continue to use him in their 2d and 3d platforming games since they'll sell more units. Unless you'd rather the same exact game with a flightless parrot on roller skates, an alpaca farmer with whiskers, or a skydiving rabbit ninja who hates carrots for some reason. So in other words, I don't like or dislike the character, if, due to his shallowness, you can even call him that.