You know before Kairi came to the US she didn't have that much muscle.Out of all the women's wrestlers I've seen in AEW where I didn't have prior experience to them, Riho is the one that's impressed the most. She's quick, she's sudden, she can sell well, etc. She reminds me a lot of Kairi Sane.
I think the only downfall of her right now is that with her size the stories are limited on what you can tell with her. She'll always be the underdog. With someone like Kairi at least, she has enough size and muscle on her where she can switch it up in matches.
If one day Riho sign full time with AEW and come to the US, she will get "bigger".