The big question mark here is Reiichi. Like how much does he know? We know he married Kaoru out of guilt and obligation, and he occasionally seems a little bit aware of what's going on. But did he keep his distance from Kaoru because he suspected his little sister had a crush on her? Is he going behind her back with Risako just because he's selfish and in love with her, or is he just unable to commit to Kaoru because he feels guilty? (Or am I just reading way too much into his little behaviors?)
I mean, I think the author could do a lot of interesting things with a setup like this, but it would require that they quit faffing about with secondary characters. Chloe/Kuroe and her girlfriend are kind of interestingly messed up, but we've just spent way too much time on them, and their relationship just doesn't have much chemistry.
This (the withheld info part) has been my main complaint about the story all along. The setup is not uninteresting in terms of the questions about these characters it raised, but the author hasn’t seemed very interested in shedding light on any of the issues that were initially set up.
Reiichi at this point is more of a cypher than ever, and except for the Exposition-Dump-Mom From Hell chapter, have we gotten any real insight into the backstory of these characters at all? Why would the author have Risako reappear out of nowhere, only to add nothing that we don’t already know—just to remind us of her existence?
When I asked similar questions some time ago, I got several lectures informing me about what “suspense” was, and how authors create interest by gradually revealing the characters to us. (Side note: I already knew that.) I can’t say that I’ve seen much payoff in this regard since then, however.
And any parallels between the secondary characters and the main plot that some readers have claimed to see seem strained at best. I don’t particularly dislike those characters, but those stories just seem to me to be all but irrelevant to the main story.
Uta stepping up and moving forward has been the main recent point of interest for me. The problem there is that at this point the logical trajectory of her personal growth takes her up and out of the story entirely.