Nintendo's Kensuke Tanabe is a fan of Luigi, and he wants to see the guy overtake Mario as far as popularity. In an interview with Game Informer, Tanabe talks about his love of Luigi, the idea of Waluigi's Mansion, and the potential for Wayoshi.
GI: Would you like to see Luigi in more games?
KT: I would love to see Luigi get to a point where he rivals Mario. I'm constantly pestering Nintendo with ideas for how to bring out Luigi more to make him surpass Mario. I like Luigi more. I kind of prefer a flawed human compared to this superstar hero.
GI: How do you feel about Waluigi then?
KT: Waluigi is something that I’m not in charge of, so that’s hard to say. Are you saying that Waluigi and Luigi should team up? He tends to appear in games where Wario appears. I guess we'd have to make a Waluigi mansion for that.
GI: I know we’re off track, but since there is a Wario and a Waluigi, is there also a Wayoshi? Has there ever been talks in the office of making a Wayoshi?
KT: Yoshi himself is everything, so I don’t know what that would be like. Maybe his eyes would be like meaner or something. Maybe he would eat stuff and then just spit it out entirely whole. Or would he would be like Birdo because Birdo shoot eggs from her mouth? Is Birdo Wayoshi? Maybe.