Lighten up and learn to take a joke.
I've always been wondering this, but what's so special about Ashley? She wasn't even in the original Wario Ware, but apparently she's really popular in Japan.
I like her design and personality. Like this pessimistic child. Who doesn't like misanthropic pessimists? Look at Nico Robin in OP for example. The sarcastic, cynical remarks are priceless. Not to mention it's a character with SOME personality, which is quite rare for Nintendo.
Same reason many took a liking to SS Zelda.
Ashley's personality is rather unique and unexplored in Japanese media as well, a place that's filled to the brim with tired cliches and tropes. On the surface, she's this cute, infantile little witch, who's clutzy but tries hard to act serious, but beneath that, there's this creepier more sadistic side to her, sure, it's mostly headcanon, but it's still interesting. I was introduced ro her character through Nintendo Power, where they mentioned that if you play her theme backwards, you can make out something about sending children's souls to hell or something.
There's also the fact that many fans see potential in her because of her abilities. Not only as a character for Smash, but many want her to branch out from WW and become her own IP. Like a rebirth of the SHMUP, Nintendo's Touhou if you will, and if you know anything about Touhou is that it's HUGE in Japan. There's actually a lot of parallels between Ash and Youhou tbh. And well, it seems devs took note of this and payed it a nod in her most recent minigame. In fact, much like Lyn in FE, Ashely is starting to get a unique spotlight in games because of her popularity.
And well, yeah, there's the pervs, but those exist for every character. It's only creepier whenthe character is a young girl. However, considering there are other loli in WW, I wouldn't be so quick to say most Ashley are pervs, because... Why Ashley then?
So yeah...
Anyway, I still say you should add her to the OP, she has a sizeable fanbase on SWF, and deserves more love. As does WW.