Daisy, my beloved.
>>534515385
One of my big wants for a Mario game is a musou and it just seems like a natural fit for Daisy, honestly. I could see her role being similar to Lana's in the first Hyrule Warriors. Mario (Link) is still the main character, but Daisy (Lana) is the secondary lead with ties to the initial plot.
Obviously not exactly the same, the weird timeline stuff and clone shenanigans wouldn't fit in a Mario game for the most part.