I usually don't watch Japanese dramas because the women usually have shrilly voices with weak character, and the men often are portrayed as rude jerks to women, who seem to fall for them anyway. I have lived in Japan for 30 years, and I can't relate to the drama characters because they are far less appealing than the people I have met in real life. Why don't Jdramas make an effort to create authentic characters?
But, I think Glass Heart is far better than most Jdramas. Yes, it is a romance without a lot of plot twists. But, I really love how the music and the lyrics work overtime to reflect the story. If you think you are going to just listen without trying to understand the lyrics, you are missing a large part of the storytelling. Lyrically, the writing is brilliant, like a rock musical. And a shout out to Kensaku Kakimoto, who did a brilliant job directing and filming. His cinematography communicated the genius of the male lead as well as the wild abandonment of the drummer unlocked from inhibitions. The rain-drenched drum scene was fabulous. I can't believe this was a TV drama because it felt like a movie. I really think his work will get an award for that alone.
The acting was far better than I see in most Jdramas, too. It wasn't overacted. Maybe the "villians" were a bit over the top, but they had to create tension for the story. It couldn't all be about finding your inner spirit through music. But, yes, the musical journeys of the characters were an important part of the story, too.
The performances were also fantastic, and so now I am wondering if the actors were actually famous as performers in real life. They were that good.
Not my style of rock, tbh, but that genre is really popular in Japan, so I am sure it resonated well with domestic audience.