I prefer Tsubame over Iino as possible spouse for Ishigami for the reasons I posted, but that's not why I replied 5 hour ago. The words "change her" in another post are what triggered me there. Changing someone is something that might work (people change people all the time), but one can't control into which direction. It sounded like Ishigami should get together with her and "save her", which in most cases wouldn't work out. It is a terrible idea. As I see it, it would most likely lead into an abusive relationship and I would advice every friend of mine in RL to not got down that road.
As I like the character of Ishigami, I don't want him to go there in fiction either. He has a very romantic outlook on how a relationship should work and would invest himself into that relationship until he is spend, if this would be RL and not a story. (Btw: Judging a story as if it is just a story, that follows a predefined plot and tropes, and ignoring, that it tries to emulate reality (at some points at least) would make reading it boring AF. The characters are written over the top, but their reactions are still very believable. That's also why it's fun to read.)
Ishigami helping her as a friend on the other hand, now that's a different story. He wouldn't invest himself too much and draw clear lines. That seems to be the more healthy option, that I wish the story would go down. I'll read it anyways, if it doesn't. He can be critical of her as a friend, too. Maybe he is even in a better position to do so this way.
It is as you mentioned a story about growth and development. The other characters had their share and I also believe, that Iino will mellow out and over come, what holds her back, as this is where the story is going. No doubt about that on my side here either. And yeah, Kaguya has been a lot worse in her Freshman year.
"Furthermore, the way you're describing Iino is completely opposite to how Aka describes her - someone who is blunt and hard-headed, but definitely not manipulative or cunning." I didn't try to describe her as manipulative or cunning. Are you referring to "to change (somebody), into a form one desires"? That didn't point to her. I just wanted to point out other scenarios on how people do change other people and how it is easier in those cases, in comparison to changing someone with issues. (They are issues, because the persons themselves can't or (worse) don't want get rid of them themselves)
If you refer to "imaging Ishigami as the slave", well you don't have to be manipulative or cunning to force your way onto others, especially, when you are blunt and hard-headed. She might not want to do it, but she just might in the long run of a relationship.
And the last point: I'm sorry if my formulation of "Iino is a fictional character, that has been written this way to attract males with a certain fetish." left a bitter aftertaste. Aka's work in building and describing the characters is awesome and they are the way they are, because of story reasons and not to cheaply attract buyers. Certainly I went a bit too far when I formulated it that harshly in my last post. Yet I didn't try to say Aka needs those kind of cheap tricks. I tried to say (and I absolutely failed to do so by formulation it that badly), that Miko herself is a variation of an archetype of person. Let me restate that last paragraph:
"Iino is a fictional character, that has been written in way, so people can see the "damsel in distress" in her, that should be helped. Therefore there is enough space for development and a way a story can move from that as starting point with enough strings attached to make an interesting journey. As this is fiction the author might come up with a way how IinoXIshigami work out, but that would go down fairy tale road IMHO. That still can be a very good read (see ShiroganeXKaguya). But it would be still unlikely, that a character like Ishigami would become happy with a character like Miko (if she actually stays an acknowledgment seeker and hardcore behavior corrector). I can even imagine Ishigami under the totalitarian rule of Miko, as a gag, which best boi doesn't deserve."
So, Miko has her share of problems, that she might (will) overcome with the help of her friends. But portraying the act of "entering a romantic relationship with her to correct her behavior/outlook on the world (to "save" her)" as something good, that's what I don't believe in. It is something that would spell disaster under normal circumstances often enough. Ishigami would end up in a weaker position to actually help her. It wouldn't help her at all and would make Ishigami and herself unhappy.