On the Meguru and Azuki bit, I agree completely with it. These things they had been fighting and confronting can change overnight in real life, as I have gone through several of these fucking things by having actually dated horrible and good people.
People are complicated and I can see a good ending happening for those two, I see that even though we ended up with a "Oh no, the couple presented at the beginning aren't together by the end" we were never gonna get that because well, they weren't a couple. Remu is simply not into human beings. Would I have liked a longer bit with Meguru and Azuki understanding each other and so on? Yeah I would, but Meguru was never just a plainly horrible person and Azuki has an ally to her to overcome the baggage, she's not alone. Meguru and Azuki's arcs are fine, Meguru and her sister (Remu) are fine.
WHAT ISN'T FINE IS WE GOT NO RESOLUTION AT ALL WITH NIJI. Niji just felt like this horrible selfish character that gets one crying scene at the end and Remu saying "Can we become friends again?" And the answer is "fuck if I know" and that's it. I'm sorry to say but the weak link of this story is not Meguru and Azuki getting together, your views are narrow, it's Niji. Niji is the weakest link, she's not a person, she's a plot point, her disgusting side appears and is sincerely not nearly as sympathetic as anyone else's and she doesn't confront it, she looks her friend in the eye and say "You aren't real." And leave and cry. That's her character, that's her. Out of everyone, she's the truly disgusting one.