It seems that outside the New Super Mario Bros. scene, Mario and Luigi don’t spend too much time together. Despite having Mario and Luigi in both Super Mario Galaxy, Nintendo’s designers kept them separated by not having in some sort of split screen multiplayer.
Well some fans would not have that, specifically a modder called Chadderz who has been slowly working at turning one of the best games this generation into a fully-functional co-op game. It’s not quite done yet, but I hope that someone at Nintendo sees this and realizes that a split-screen might be totally worth it.
Especially if the Wii U can support to game pads, then the next 3D Mario game could totally have not just co-op, but dual touch screen, motion controlled, panorama view split screen.