Hey I mean, we have three Links. Three Marios isn't out of the question, but if we were to get one I'd say Paper Mario is the way to go.
Also, to rewind a bit to an earlier discussion of Donkey Kong characters, I had an idea for something they could do in the next DK game. There's the trio of Lanky, Tiny, and Chunky from DK64 who have largely been forgotten since then. Tiny has had appearances in a few spinoffs, and Lanky in Barrel Blast, but that's not saying much, and Chunky has gotten nothing.
So this won't happen, but I'm thinking it would be cool if they came back as a trio in either a DK64 remake/enhanced port or a new Country game altogether. They could even market them as the "lost Kongs", lol. The three have such great potential, even Tiny who's a lot like Dixie but could have some uniqueness with her shrinking ability. Hell, when I was a kid I'd make up plans for a DKC4 involving the DK64 gang + Dixie and Kiddy as a cast of seven interchangeable characters as they fight the Kremlings and K. Rool, who of course has some new persona.