Onto whom I believe the new Mario representative will be. While Rosalina is a significant character in Super Mario Galaxy 1, her very brief cameo in 2 doesn't really constitute as bein' in two games (let's be honest, does Mario Kart or even the sports games really
count?). There's the additional fact she's never been playable in a major title as well, whereas Peach most certainly has. Rosalina definitely has moveset potential in the fact she can use magic and has lumas, which would perfectly differentiate her from Peach, but moveset potential certainly isn't enough. I don't believe Rosalina will get in, period. Not without high fan demand.