The only way they'd be able to change my mind is by making Himari have some sort of profound social/cognitive issue or some sort of personal trauma. A teenager who grows up without an idea of what romantic love should feel like is such a statistical anomaly that they should at least try to explain it somehow.
Idk, have you read Bloom Into You ? Because it's a similar case and as far as i remember Yuu never had any trauma of some sort.
That music is not integral to the story doesn't mean the characters can't have at least some form of connection through it. And I mean, Himari literally falls in love of Yori while singing
You answer yourself, she fall in love of Yori singing. Nothing more, it's not a manga focusing purely on music. I don't get why you found it bad based on something like that.
we need drama because otherwise the MCs will get together for reals and the story will be over, so here, padding
It's not a one-shot, of course we need dramas of some sorts to get the story going but i'm must say that so far the dramas have beenwiped out pretty easily. The misunderstanding on HImari's "love" and Yori's one could have take more chapters to get through and what happen in the last chapter could have take ages in others mangas.