In my opinion, if a character is colored like another (Peach to Daisy, Lucas to Claus, etc.) they're still that character, only with a different palette. If a character gets a new model, like overalls Wario, female Pokemon Trainer, or Dr. Mario, they're still that character (the female PKMN Trainer is still the PKMN Trainer), just a different form or appearance. But when a character gets a model swap to a whole other character, one that, even if they have similarities, clearly is another character, it's a much different story. Lucina dressed as Marth, but she isn't actually Marth. And Marth is the character in Smash. It might be pretty much the same thing aesthetically (which is debatable and varies between characters), but character-wise it isn't. And I'd guess that probably does matter to Sakurai.