Peach and Daisy are basically 1:1 in Ultimate so it does basically boil down to personalities with them. Simon and Richter is literally one difference and it's that Simon's holy water has fire properties. That's what I'm getting at: you have characters with miniscule differences between them and even then it was decided to make them seperate characters. Mashing multiple ARMS characters together in the same slot doesn't work the same way. Hero works because he has literally no real personality and the Koopalings work because they're not the key focus in their character.
Having different animations means they literally have different gameplay. Calling them 1:1 is misleading. 1:1 is only for alts like Hero.
Animations have always affected gameplay. It's not much, but that's why Daisy cannot be an alt. Unique animations that make the alt situation impossible. It's not a personality factor alone.
Daisy's difference is very tiny bits of gameplay in the end. Personality can easily be done without changing hurtboxes at all during animations, as we've seen with Byleth, who actually has slightly different animations but directly has the same hurtbox.
I guess the real question is whether a few personality exclusive animations warrants the need for an entirely separate character. I wouldn't think so but Sakurai does work in mysterious ways.
PS I forgot about DP's different final smash because I don't really believe in using Final Smashes. They're horribly uncompetitive and few of them are balanced in any way. I only ever use them when my friends and I are playing a mass FFA with items and hazards on.
Pretty much. Animations is the difference between Daisy and Peach that actually matter. They literally were identical in tons of games beforehand and still have no real differences. Alts can even have different victory screens, so Daisy's split is not remotely notable at all. If she had no animation changes, she wouldn't be an Echo either. The reason for the Alt to Echo split was stated directly by Sakurai that they can't have any gameplay differences, no matter how minute. All Echoes apply to this. As they have some kind of difference, this affects results. Personality was a secondary factor, and you can still decently get that with taunts and voices, as long as they don't affect hurtboxes/hitboxes. As Byleth shows, it's clearly doable.
Combined with unique victory screens, and it's pretty easy for Daisy to work as a Peach alt overall. However, as Daisy was never a real alt of Peach, it doesn't mean much. Dark Pit was the only actual alt of a character outright at any point in time. Other alts were references otherwise. Generally, he's made characters who are Echoes and removed an alt that references the character. That's why the Echoes beyond Dark Pit are not real examples of any kind of Hero situation. We have yet to see a case beyond Dark Pit(who had gameplay reasons for being split off instead of being an alt) where they removed a direct character alt and did it purely for personality reasons. It's no wonder Alph isn't being split off. Him nor Olimar have personalities in Smash. It relies entirely on gameplay at that point. Personality absolutely can play a role, but pretending it's the only reason is clearly ignoring the core reason for the clones, which was "different gameplay" in Smash 4. Besides that, nobody else was an alt beforehand and being split off in a game before Smash 4 directly did so.