LaniusShrike
Smash Champion
Waluigi is a dirty, try-hard, pseudo-romantic, antisocial creep.
I'd like him in Smash 4. I definitely would, but I think that sums up his personality (since you guys were talking about his personality.)
We all know he's dirty, both literally and personality wise. (looks like he has bad hygiene, is a thief, is kinda vulgar with his crotch dance, etc.) We know he tries hard, as per him thinking everyone is always better. The pseudo-romantic appeal totally goes with the moustache and it's gimmicky enough to make him a fun character, he's obviously antisocial just by his behavior and no one liking him, and he just screams creep.
He has enough moveset potential and enough originality to make for an amazing character, totally unlike "just another fire emblem rep" or "another pokemon," or "another mario." What a lanky, sporty, depressing purple giant he is.
I think we can all agree he has a "romantic" or "magician" image to counter wario's "biker" appearance, and we know nobody really likes him that much.
Mario just gets the ladies by being #1. He cares and does everything right, apparently.
Luigi's a total dweeb who's mildly successful
Wario doesn't care about anything but himself, and it has done him well.
Waluigi cares a lot but just can't manage to do anything right.
... hmm, yeah, now that you mention, I'm pretty sure I've seen Waluigi hitting on girls at clubs before... Like, in every club.