I don't know why it took me until now to really think about it, and I know it's been talked about in the thread already: Takamaru. I remember the interview, I think it was, where Sakurai has stated he wanted the character in but retracted the idea because of his lack of over seas popularity. Honestly, and no offense at all to people who like WFT but...the avatar from Wii Fit. That makes the cut but a shuriken slinging, katana chopping warrior doesn't?
And no, I'm never letting this go.
While I like how Sakurai wants characters and such to be liked by the whole world and not just Japan or vice versa, it seems odd that it was for that reason stated above he didn't put in a character he wanted, even if the character could be appealing on his own to the West. Just look at Fire Emblem in Melee or Lucas from Mother 3. At the time of Melee and Brawl respectively, most all western players, even Nintendo fans, probably couldn't recall those characters at the time and now they are hugely popular here. I think Takamaru would be seen in the same way, even if you couldn't recognize his game, he's still a cool character in his own right. He's a samurai for god's sake.
But that was just a random thought of the evening.