Does anyone else here think that Hyrule Warriors might be the first spinoff title to receive a playable character? I've always sort of felt like it was possible. I'm playing Hyrule Warriors Definitive Edition right now, and it's crazy how much love went into this game. There's tons of content spanning many eras of Zelda. On top of that, they've remade the game twice now, with new upgrades coming to each version.
When discussing Zelda characters, people have only focused on the mainline characters. I could see Lana or Linkle happening. Everyone has a hard time deciding who the best possible Zelda newcomer is due to the nature of characters who are not Link/Zelda/Ganondorf. Lana and Linkle have both appeared in 3 titles which all have decent differences between them. Lana is one of the main characters, and Linkle now has her own full story as well. Both characters, especially Linkle, were well received by fans.
I understand thinking spinoff characters won't happen, but I'm saying this in the same thread that supports Waluigi and (sometimes) Daisy as characters to represent Mario spin offs. Nintendo clearly believes in the success of Hyrule Warriors, so why not have a character in Smash?