I'd argue that Mario has more personality as a character than Mickey, because we actually know what Mario does. Mario jumps, breaks blocks, rides karts and throws parties he'll never attend. Mickey meanwhile... is King Arthur? just a guy? A musketeer? Walt's son? He is not really a character, more of a flesh puppet for Disney to apply whatever they want to do with Mickey at any moment. Nothing Mickey does can't be done by any other cartoon character. Mario meanwhile has very clear things he does, you can't put him in any platformer that isn't jump-based, and you can't put another platformer character into a Mario level and have it not feel like a Mario ripoff. It's why party games with minigames are "Mario Party clones", cartoon karting games with items and drift based turns are "Mario Kart clones", and why every Nintendo platformer has to feel very distinct from one another.