I think my least wanted is a toss up between Pokémon and an RPG character that isn't Isaac.
I have nothing against Pokémon other than it has stupid amounts of representation already, and it's just the most obvious choice for Nintendo to make. I haven't played Gen 8, so I have no attachment to any of them. That's not to say other people don't, but can we just...wait til the next one? Thanks.
Then RPG character is kinda funny. I like RPGs, but that doesn't mean I want every RPG character under the sun. I've already got Hero, Cloud and Sephiroth, the only one missing for me is Isaac; that's a personal connection that needs to be realised for me. 18 years of "That would be such a cool moveset to have in Smash." The spotlight on Golden Sun is a bonus at this point.
But screw all you other McJRPGs. I don't want you getting in over Isaac, that sucks. Hero is fine, he's the Grandad of traditional JRPGs and I love him to death. Sephiroth was low key my most wanted Squeenix after Cloud, he's a big deal. Pythra I didn't like, that actually caused me to lose the most hope as I thought the RPG picks were all gone now for Fighters Pass 2. Lloyd from Symphonia, I actually do like! But I knew that if he got in before Isaac I would be so let down, even though I do want him to get there eventually (Isaacbros and Lloydbros for life).
So I'm looking at you, Dragalia Lost, Atelier, PSO, Ys, and SMT. Begone.