Shigeru Miyamoto, Mario co-creator, and Yoshiaki Koizumi, director of Super Mario Galaxy, participated in a recent Iwaka Asks Interview where they both discussed about the latest Mario games. Koizumi stated that he has certain regrets regarding Super Mario Galaxy. 

To begin with, he would have liked to have Mario and Luigi to be able to play together in a 3D Marioan idea he has been pursuing since Super Mario 64, but Koizumi would also  have liked to make Super Mario Galaxy a title more suited to girls.

These two issues where, somehow, fixed in Super Mario 3D World for WiiU, the latest Mario 3D game to be released. 4-player co-op game mode is available in the game and the addition of Princess Peach in Super Mario 3D World makes the title more appealing to women in addition to men. When he was explaining these points, Miyamoto came on the scene:

Just so there is no misunderstanding, I should point out that this doesn’t mean we’ll never make another Super Mario Galaxy game

super mario galaxy 2 Rumor: Nintendo could develop more 'Super Mario Galaxy" games | VGLeaks 2.0

The same team can’t make both at the same time. And we can’t bring in a second party and slap the name Super Mario Galaxy on it. I suppose we could idealistically make both in Tokyo, but we want to do something new too, so there was that dilemma. Personally, I would like to take on a variety of new challenges with Super Mario Galaxy and design 2D Super Mario games in an easy-to-understand way within certain restraints.

Would you like to play another Super Mario Galaxy title, or would you prefer to play a totally new 3D Mario on WiiU?