Cosmic77
Smash Hero
I actually think the current icon works well enough. Doesn't exclude the Wario Land series, and it's something that most people would automatically associate with Wario specifically (mainly because the number of characters' names starting with a "W' is lacking.)Wario's icon bugs me, it's so generic. I'd change it to the Wario Bomb or just a bag of treasure to represent the character as a whole.
Plus, it's the icon in virtually every Mario spin-off game, just like Yoshi's egg.