Ok, you can believe that, and I'm going to change your opinion. But I just want to mention this.

All of the characters you mentioned have movesets over 10 years old. And Sakurai will never completely change more than one move at a time. If those characters were released today. Sakurai most likely wouldn't have went cold turkey and just gave them basic attacks. The only reason Dark Samus, Ken, Daisy, and Isabelle have similar moves to the counterpart is because that would be the only way their moveset would work. Think about this:

Joker's moveset represents Persona 5 very well (Action, Ninja-esque protagonist, Arsene)

Hero represents the Dragon Quest series extremely well (Spells of different power, choosing spells, RNG, MP, various Protagonists)

King K. Rool represents his character very well (Uses material from Donkey Kong Country, Donkey Kong Country 2, Donkey Kong Country 3, and Donkey Kong 64. The moves that were made up, make a lot of sense for the character, they fit his personality and his brute force well)

What do all of those characters have in common? They're new.

Smash Bros has a new standard for character movesets that wasn't seen in the previous games. Sakurai would only be fine having clone characters if they were under the "Echo Fighter" name, because that is what makes them special, the fact that they're not special. The non-Echo fighters on the other hand, have completely new movesets.

Like I said, of course every character ever made in the history of ever has SOME moveset potential, but if it's not enough to create a diverse and fun moveset that references their games, I don't think Sakurai would add them in.

Let's just agree to disagree though, I personally believe that Sakurai wouldn't add a character if he has to make completely original moves that the character can't do in their games. If you believe that, it's fine, and I understand your point.