The idea for making the Mario characters and enemies more expressive in Super Mario Bros. Wonder than in previous games (including the New Super Mario Bros. franchise) came during an early part of development. Masanobu Sato stated, in an Ask the Developer interview with Nintendo, that they wanted to "implement more engaging and functional ways of using 3D models in this 2D platformer."

Looking back at the New Super Mario Bros. games, Sato recalled that "It's a well-known story within the company [Nintendo] that Miyamoto-san said designing Mario's nose to be big back in the day of the very first pixelated Mario made it easier to see which direction Mario was facing. But if we set Mario's nose to face the direction of travel, like we used to, with a modern 3D model, you wouldn't be able to see his facial expressions."