A Daisy sport based moveset isn't really all that redundant since Peach only uses a Tennis racket and golf club and simply swings them, that's it. Still a lot of moves that people could give Daisy and completely avoid giving her anything from the Tennis or Golf Mario games.
Well, yeah, actually, when your main gimmick has already been done by another character from the same series for the past three games, it's pretty redundant.
You can swing those weapons differently, but at the end of the day, it's still a moveset using a golf club or tennis racket, and doesn't really bring anything new or interesting to the table.
I honestly think you maybe putting your dislike for Daisy (if you have one) in your analysis of her getting into Smash. Especially when you said a Shy Guy is more likely then her, as I stated above Daisy is often listed with characters like Waluigi, Paper Mario and Captain Toad/Toad as to who people think will be the next playable character for the Mario series.
While popularity is a big factor right now due to the ballot, this discussion is about Daisy getting into any Smash game, not necessarily Smash 4 DLC.
What you seem to be forgetting is that popularity is not the only factor. Especially outside of the ballot. Look at the base game: highly requested characters like Mewtwo, Ridley, and King K. Rool did not make the cut. Characters that hardly anyone asked for, like Duck Hunt Dog and Wii Fit Trainer did. The importance of popularity is greatly exaggerated. Uniqueness appears to be the biggest factor when deciding new characters, and there isn't much about Daisy that is truly unique.
Her actual level of popularity is hard to gauge, anyway......on some sites (GameFAQs in specific),
Daisy is a meme character comparable to the likes of Reckless Wii Remote guy, Shrek, and Goku. There were dozens of trolls pretending to be hardcore Daisy supporters. Daisy obviously has an actual following, but we don't really know how many there genuinely are thanks to all the jokers in the mix.
You also need to look at the Mario roster. Bowser Jr and Rosalina tend to miss spinoff games, while Waluigi and Daisy are almost always present. And just the opposite is true with the main Mario series.....Daisy was only in one non-spinoff Mario game and Waluigi has never been in one. Rosalina and Bowser Jr are regulars.
Who made it into Smash? Rosalina and Bowser Jr. This suggests that Sakurai looks at the main series and picks characters based on their importance to it. While I don't think Birdo would get in before Daisy, I can certainly see why someone might feel that way......Birdo actually still appears outside the sports games unlike Daisy.