Just a random thought I had when thinking about underrated/overlooked Mario villains. Seriously though, she fits the bill better than pretty much any other character in the series:
1. She literally looks like Princess Peach, except somewhat Wariofied
2. Her battle uses emotions similar to Peach's in Super Princess Peach
3. The whole character feels like a subversion of the whole 'dainty princess/damsel in distress' trope, with the regal princess like character turning out to be a horrific demon instead.
Honestly, if you wanted a Wario version of Peach for a sports game, you've got one right here. She'd certainly fit the bill better than making some random goth girl as his sidekick, or trying to treat someone like Captain Syrup or Mona as something different to what they actually are (their own characters with their own personalities).
The thing with Wapeach as a concept to me is that I am not the biggest fan about how some approach it.
Wario in terms of design is an exaggerated Mario and Waluigi naturally does the same for Luigi, since he in turn is very similar to Mario.
With Peach you can't really do that, since she has a very restrained design, so the initial pitch of a violent brat with an axe vs the dainty, kind princess, makes sense for me as a way to toy with a anti-Peach.
Alternatively Syrup to me fits it better from a role stand-point, being a pirate and enemy to Wario. Terrormisu can fit that too, but I fundamentally don't particularly agree that a ''Wa'' counterpart for anyone else needs to have Wario features, because Waluigi himself only has them incidentally due to Luigi being so much like Mario.
I think on the surface this makes sense, though Terrormisu's resemblance to Peach is purely coincidence and not something intentional like what Wario was originally trying to do to Mario. I want to bring up this Tumblr post for making an excellent point that being a "Wa" character isn't just about being a exaggerated foil, but being that way for specific reasons. Wario was the anti-Mario because he wanted to usurp his position in Mario Land 2, and Waluigi is the anti-Luigi because he wants so badly to be recognized that he copies someone else. It is funny how much lines up with Terrormisu for what is coincidence in-story though, especially the final battle having emotions similar to Super Princess Peach. It almost feels intentional from a designer standpoint, but there's nothing in the story that suggests these implied television show characters have a personal vendetta against a princess who is never mentioned otherwise.
I would argue Syrup also subverted the damsel in distress trope in the original Wario Land especially, though again outside of that there's not much connecting her to Peach besides stealing that statue (which isn't given much depth beyond "pirates like gold"). I do think Syrup could be an interesting foil to Peach, but I've moved on from calling her a "Wa" version because truly, we don't really need any more Wa characters. It's not like they ditched the original Wapeach pitch for no reason, because then who do you create to be her tennis partner?
Yeah I don't think we need any more 'wa' characters, and I'd rather we had more unique characters to fill those roles instead.
Like I'd rather have Captain Syrup than any version of Wa/Walpeach. And I'd rather have just about any interesting Wario character than Wariofied versions of say Daisy or what not.