Totally agree that Inaba would be stronger. Alas, she's not in Morning Musume so she's not going to get these kinds of opportunities. There are countless skilled idols in groups nobody's heard of. What makes Ishida a unicorn is that she is in a flagship group. One that, as you say, nobody would expect real talent from.
It's like, say, Lance Bass from NSYNC being invited to Dancing With The Stars, but your much more talented classically trained dancer friend who has a minor recurring role on General Hospital will never get the call. Bass had skills for sure, but not champion level skills.
Speaking of Inaba, I was watching a
classic performance by Aichan the other day and it struck me that Manakan is really the only one in H!P these days with that level of stage presence. She and Ai are women whose preternatural physical grace stood out from early on, whereas with Ayumi, she has talent, but I would say that her strongest points are that she's competitive and really
puts in the work.