As others commented before, this needed some more development on the main couple, as this follows the "main couple relationship confirmation marks the end of the manga" for the male oriented romantic genres "dogma" is hurting all these publications.
I wish more series went further, but I guess that's not what the market wants. And I'm ok with that, as the author and the people on the editorial department need to eat too.
The only thing that I would like is that the authors had the freedom to self publish follow-ups of their stories by other means (internet is a thing), whitout legal issues. After all, if an axed series is not lucrative anymore just stop the publication and leave it be free, and if then it gets popular again they can just serialize it again. Some series now get the Pixiv->Magazine treatment, so maybe the inverse way could work too, on a business oriented view.
And if the author ruins it, let your mental cannon prevail. I'm one of the few that liked the original 4 alien movies, not only 1&2, but was really dissapointed with Prometheus (I'm mad with you Ridley Scott, you ruin it, pass the baton and let Blomkamp do his thing!).
Well... going back to this manga... Even if the final arc was pretty boring and rushed, I really liked the aproach here on the side stories. There can be lgbt couples mixed within the story with it not being treated as such a big thing, and there can be main lgbt couples too of course, but lots of media now just force the thing and treat it like is the only thing moving the fiction world, and that not only hurts the story (if there is one), but the long term sales. And that is the same problem as before, a hollow premise being the only core of the work, and no being anything anymore after that core dissapears ("the couple is a thing now, END", "I want to be a pro -insert job/art-") makes for a short lived franchise. If it is bad, it is bad.
And the pretty pictures are a plus too, after all those black thights panels were really good, but were kind of wasted on that girl.