Is Naotora popular? Like no tea no shade no pink lemonade I have no clue since they haven't done a popularity poll with her in it but her reception didn't seem that good and not too many people use her from my experience online.
Tho out of all the guests aside from Momiji & Rachel she probably has the best chance of coming back since they own the rights to her unlike Mai and the VF's. If she does hopefully they'll expand her moveset and make it better.
She may not be popular on FSD due to most hating her personality and moveset but actually quite a lot of people use and have bought her, she's in a lot of YT videos and she's mainly aimed at Japan plus she was a fan favorite from SW, so I'm sure she's popular enough, plus TN has her in regular DLC circulation, and KT will likely ask TN to add her again to promote the SW series
Plus she's a skillgate character and those sell well regardless of who it is, she probably has sold just a bit less than Mai actually, Mai is more iconic but she has less outfits to start with, no Japanese voice and her learning curve is much steeper than Naotora, those can be factors in how well a character sells
Moveset wise I say she doesn't need many new moves, I feel she's fine the way she is. All I want is:
(her jab with her 3K kick)
( her P plus her 3P
(lets her do the third hit of her KKKKKKKK string and all the follow ups from that point
/
(lets her do the third and fourth attacks from PP2K
Replace KKKK6K with KKKK6P(based from the 66P command) or just add it as another follow up
Make 236KK safe since there's no delay allowed and she's at a disadvantage regardless if it hits or is stagger escaped, plus it's two mid kicks, the opponent shouldn't be hit by it
Improve the input feel and ease of