People really don't give Spring Man enough credit. He's way more than just box cover boy, if the intention was to toss him aside when they discovered who was most popular, why make Springtron? Springtrons existence to me sets in stone his mascot role. The fact he's featured in way more of the unlockable art certainly doesn't hurt. Not to mention he's the fact he was the assist trophy to begin with. That he and Ribbon Girl got the Mii Costumes. He was already the one chosen to represent the game.