To say, I read all of this on weebcentral and wanted to get my thoughts out somewhere, but the character limit and frankly shitty comment section on that site blew chunks.
I think it was pretty good up until that final chapter. I don't think Futaba and Taichi had to stay together, and if given more focus on Taichi's POV instead of just handwaving it for the 7 year timeskip, I think it could have been a really great way to add on to the conversation about finding your happiness, things changing and figuring yourself out. My main want was them all staying friends despite everything, because regardless of how they feel about each other, platonic or romantic, they were included in that idea of future happiness. Which I personally believe did happen.
With Masumi I don't really see it as unlesbianing her (I saw a lot of people on weebcentral claim that it was), because I feel like her whole arc was nailing down her identity, basically self-ostracizing herself from others, and thus not allowing herself to understand even herself. At least that's what I took from her fight with Mami in ch. 45 and her talk with Taichi in ch. 51 (I mean there she fully says it's perfectly valid option that sometimes you just can't decide). That plus the fact she does try to date men (not even as some sort of cover/a beard) and outside of Futaba didn't have any interest in other women, to the point though it was kind going to be like how the author addressed Futaba's original feelings for Toma (ie, more idolizing type of like than love). Then of course the end says she has decided she can't decide between men or women and likes them both. So I think having her being bi in the end works.
I feel like my only hang up with the ending is with Taichi and Toma, because all of Taichi's build up feels like it's amounting to him not feeling the same but still wanting his best friend in life, especially in that final beach conversation just capping it off. But then they're married in the final chapter? Idk, it feels almost like the original draft to the story 20 chapters before and not what it was by ch. 53. I'm not against it, just felt so out of nowhere and at the expense of undoing a lot of Taichi and even Toma's development to an extent. And with the POV being Toma instead of Taichi in the Final Chapter, the character who I feel like would have benefitted the most from an internal monologue in that final chapter, it feels like there is this gap of information that COULD have potentially subdued that feeling of 180. Feels almost like after ditching the original BL idea, the author regretted it at the very end.
Idk, I just have a lot of thoughts and even ways I can personally relate that might be shaping my opinion I guess. BUT, generally, outside of the more word vomiting chapters toward the end like in Kensuke's room, the final chapter is the only thing that really felt wrong/out of place.
Ignoring that final chapter, it's probably an 7/10 with some actually interesting writing/conversations on sexuality, happiness, social life/peers (I particuarly like how Toma and Kensuke's beef ended, with neither's identity or experiences being invalidated and, mainly Kensuke, valuing their friendship more) and just wadding through your own emotions in general, with only a few eye-rolling/rambly parts that felt a bit preachy/soap boxy.
With the ending it's like a 6/10 because of how much it undoes and feels tacked on as well imo.