She has to be the greatest female wrestler of all time, no?
She's carrying on the tradition of true legends like Chigusa Nagayo, Manami Toyota, Meiko Satomura... Io been in that conversation (top 5 DOA) since she was like 25 years old, just based off her accomplishments in the joshi scene.
To me what separates her from those other joshi GOATs at this point is that she's doing it outside of Japan too and succeeding in WWE against all the odds. Like, idk if Chigusa works outside of the context of 80's AJW. Idk if Meiko succeeds if she has to be anything other than Badass Joshi Final Boss Satomura-san. Idk if Manami Toyota would come across as more of a killer than Pentagon Jr. Idk if you can have a Historic First Ever Women's War Games match and have it not be a flop without Io in there doing spectacular shyt that only she can do.
When it comes to NXT, I can't think of another "big name free agent" who got booked as weak as Io and still managed to get over so strongly. Asuka (rightfully) got the red carpet and a historic unbeaten streak.. Nakamura and Finn Balor were pushed as gods from day 1. Io gets jobbed out clean in the Mae Young finals, jobbed out to Sonia Deville in Worlds Collide, jobbed out to Shayna in multiple failed title challenges, pushed aside to make way for Rhea's push to the moon...
The only thing that prevented her from being Hideo Itami or Tozawa status is the fact that she just so happens to be
literally the best pro wrestler in the world. Here we are 2 years into her run and she's just now getting her first notable win (an undercard match vs Candice & some TV's against Mia Yim + jobbers are her only other singles wins period) and it doesn't even matter because everybody already knows she's the best