i admit my personal disliking of mm3 is mixing up with my actual opinion about Daisy however keeping it complety 100% i will say Daisy really doesn't differ that much from Peach per see.
Mm3 is so pressed on Rosalina and all that but fails to realise the simple fact that Rosalina only shares physical features with Peach FOR A GOOD REASON that we all know at this point and that's it , meanwhile Daisy who is no related to her not only shares the base body Peach has , but also has the same abilities overall only changing hearts with flowers , that's it.
Everything Daisy supposedly can do , Peach has already done it, does it better or simply does things that Daisy can't , including floating with her dress.
Now that you think about it is hilarious that both Peach and Rosalina can somehow float and use some kind of magic of some sort but they still remain vastly different overall , meanwhile Daisy copycats Peach most of the time.
At least characters like Luigi have an excuse to do this because he is literally Mario's twin , but even Luigi has a very defined personality and has evolved into his own character even if he physically looks like Mario.
Daisy simply isn't completely unique in any area you put her, she doesn't look straight off like Peach but she is clearly based on her and like i said her body is literally Peach's but a tad smaller and this isnt even limited to the main dress, the costumes are staright off Peach's IN CONTRAST to Rosetta who has a different tennis dress, swimsuit , main dress and so on, and even if she doesn't act 100% identical like Peach she still has 99% of her abilities based on Peach's and her behavior is still flirty and girly at times.
Adding more fuel to this fire, Daisy doesnt have a background that adds to her moveset either, unlike Peach using a frying pan like in the RPG game or Rosalina using her wand like she does in Galaxy.
Finally, i wanna point out once again that characters that were not created by Miyamoto or Koizumi are usually neglected and this is a fact.
It's not coincidence that all the characters sans the ones not created by Miyamoto or Koizumi have a lower class treatment so let that sink in.