There's probably a few people out there who know Ashley by name but don't know she has anything to do with Wario. Most people would call this a bad thing but I'd consider it a testament to how memorable and varied the WW character designs are.
I think if Nintendo were to experiment with breaking the "Mario Mandate" a little, Ashley would be the perfect character to use - she's unlike anyone else in the regular Mario roster, but also doesn't have a confusing backstory or strange design - you can see her with the skull jewel; crown-like headband and little devil friend on her shoulder, and instantly know what she's all about, she wouldn't bat more eyes on a Mario Kart roster than Daisy when Mario Tennis 64 came out. Die-hard fans get a character they know well; while casual fans just see a moody little witch.
I think if Nintendo were to experiment with breaking the "Mario Mandate" a little, Ashley would be the perfect character to use - she's unlike anyone else in the regular Mario roster, but also doesn't have a confusing backstory or strange design - you can see her with the skull jewel; crown-like headband and little devil friend on her shoulder, and instantly know what she's all about, she wouldn't bat more eyes on a Mario Kart roster than Daisy when Mario Tennis 64 came out. Die-hard fans get a character they know well; while casual fans just see a moody little witch.