Despite Ganondorf's inaccurate moveset, many people still love playing as him. His players' only consistent dissatisfaction was that he didn't ever use a sword, now he uses a sword for his Smash attacks, and
people are ecstatic, as small a change as that is. By now, most players have gotten used to Ganondorf's moveset and enjoy it, inaccurate or no. Similar to how all clones and semi-clones have just stayed that way, because if you change the whole character, then you risk alienating the people who liked the playstyle, even if it's not tapping into their true potential. For every person who is disappointed that Ganondorf's still mostly the same, there's hundreds that have either always liked or grown to like his monstrous attacks as they are.
And if you asked Ganondorf players whether they'd want Ganondorf to still have the same moves or be removed from the game entirely, you can expect what their answer would be. Same for all the echo fighters and semi-clones that are coming back this game. Most people were sure that they'd all get cut, and that characters like Pichu and Wolf would never be seen again. Instead, they're just happy the characters are back at all. Young Link has the potential to have a Majora's Mask moveset with mask transformations and abilities to make him really unique and standout, but he's still the same. Most people just think it's awesome he's back. The only people I've seen be dissatisfied with Smash Ultimate's roster are the people who barely play Smash and wanted 2/3 of the characters to be cut so they could add a bunch of new fighters and no clones.
Really, as long as the character is fun to play, that's all that matters. I know Dark Samus with a totally unique moveset is available as a Brawl mod, and Chibi-Robo (my other major want) is playable in Super Smash Flash, but both of those lack the feel and polish that can only exist in a genuine Smash game. There's a reason most people stick to official characters and versions of the game, with Project M being the exception. If a character's moveset is super unique and accurate, but not fun to play, then it's pointless.
Yeah, Dark Samus as an echo fighter would be disloyal in the sense that it's obvious there's untapped potential for the character, and it'd be a unique and interesting fighter if given the chance. Shadow the Hedgehog being an echo fighter would also mean we wouldn't get to see him shoot aliens with an MP5, sadly. But more echo fighters are inevitable, otherwise they wouldn't have labeled them and announced Daisy like they did.
Some people are running with it in absurd and excessive ways, with little regard as to how much sense the echo character would actually make. At least Dark Samus is one of the more reasonable options, and would show some love to a franchise that hasn't gotten much in the past, even if they didn't go as far as they could or should've.
After all, Sakurai is the same guy that added Fire Emblem characters to Smash before their game was even released/released in the West--
twice. And each game added one or more new Fire Emblem characters, while other franchises got snubbed. By Ultimate, Fire Emblem has four totally unique fighters, a clone, and an echo fighter. Yet despite all that favoritism and representation, Fire Emblem fans are still earnestly requesting more characters like Celica and Chrom, even as echo fighters. Like, is 6 characters not enough? Give some other franchises like Donkey Kong or Metroid a chance for a change. We already have a Marth clone and echo, do we need more? I'd rather have Dark Samus as an echo than another Fire Emblem echo. Maybe Sakurai realized he went a little too far with Fire Emblem (I have to imagine he's become aware of it one way or another) and has neglected Metroid for a while, so he gave us Ridley, and maybe might throw in Dark Samus as an extra bonus to make up for it.
At this point, it's all just speculation. It's entirely possible Dark Samus is still an Assist Trophy, but just hasn't been shown yet. It's entirely possible that Dark Samus is a 100% unique character, though that's the unlikeliest outcome. The other two options are echo fighter or semi-clone. It'll be something or nothing, for better and for worse. Either this is one of the biggest Smash teases since Ridley in the Melee trailer/intro, or Metroid gets two new characters in the same game.
Who knows. I actually voted for Dark Samus in the ballot, since I figured Chibi-Robo wasn't popular enough to warrant a character at the time, and Ridley had been vocally shot down twice. I said in my vote that Dark Samus's assist trophy showed the potential for a whole unique fighter, as opposed to needing her to be a clone. Maybe, somehow, my vote landed in his lap and inspired him, and in a few months we'll see a second completely original Metroid character join the roster. Or it got buried underneath thousands of requests for three more Fire Emblem characters. We'll have to wait and see.