A common gripe with this show is the side characters. And to be clear, I wouldn't watch a show about any of them. They're not particularly deep or compelling, at least in a vacuum. Their relationships with the main character aren't compelling either, again, at least in a vacuum. That is to say, if the plot was changed to something we're more used to seeing in a romance, this show would be hot garbage.
The problem with this show is that it's labeled a "romance". It is NOT a traditional western romance that focuses on the relationships between two or more people. It's a romance between the main character and his own life. Despite what is presented to us, there is no "main couple". There is only Kousei, and almost everything else should be treated as metaphoric.
If the main character is the locus of attention, then what's the purpose of the side cast? Why does the show take multiple episodes to deal with two of Kousei's rival performers when they have almost no bearing on his own story? Why does a certain character experience unrequited affection for the main character?
It's because Kousei is not, by himself, relatable to anything but a tiny fraction of viewers. Most people won't relate to all of the side characters either, but they serve as necessary reference points in trials similar to Kousei's. Conversely, there were a character in the show that *actually* understood everything Kousei experiences, it wouldn't be interesting. The side characters keep the viewer from sinking completely into Kousei's psyche and being unable to understand it, and instead provide analogous experiences that a greater number of people will understand, helping them bridge the gap between the viewer and Kousei.
It's a very monologue-heavy show. The visuals and music are very strong and suited to the show thematically, but the real meat of the whole thing lies in the thoughts of the characters. When this show puts a character's thoughts on display, it's poetry that is usually very easy to digest yet is thematically meaningful.
It's not a tutorial on how to love life, but it will tell you what it feels like and what it doesn't.
