I wrote a blog about this a couple years ago, let me find it....
And here it is :
Ok, I have been saying this for a really long time, and I await the ridicule that will come from this comment, but Luigi, is the most underrated video game character of all time. Nintendo initially dropped the ball with this one back in the American version of Super Mario Bros. 2, what with Luigi and his flailing feet of doom.
Now while Mario has had many great games, and Luigi is always in the shadows, or locked in some ghostly mansion, or cage, or various other places that Nintendo can think of to hide him, Mario has yet to ever actually completely save the princess, or for that matter, move their 25+ year relationship any further than it already is. If Luigi were to be the main protagonist of the games, he'd already have married her, had kids, divorced her, taken half the mushroom kingdom, forced Bowser into some weird alternate reality where he's a toaster, and then started dating Peach's younger sister. Alas, that will never be the case, let's just hope that one day, someone, somewhere will make a half-way descent Luigi game, lest he snap and starts having Mushroom soup for the rest of his days.