Etan Weisfogel’s review published on Letterboxd :
There's a moment early on this film that nicely summarizes Damien Chazelle's approach to music and art: Ryan Gosling, sitting at his piano, puts on a jazz record, which begins with a complicated piano riff. He stops the record, plays the riff on his piano exactly as heard on the record, messes up, then spins back the record, replays the opening, and mimics it again. It's the same methodology behind the "Play one wrong note and you DIE" premise of the Chazelle-penned Grand Piano and the keep-the-tempo obsessiveness of Whiplash. Great artistry is about hitting your cues, keeping the rhythm, getting the notes right. Interpretation, originality, feeling are ignored in favor of technical proficiency. One wonders if Chazelle's kindergarten teachers indoctrinated him with this draw-inside-the-lines ethos or if it developed naturally from a lack of imagination.
It's an ethos that extends to his formalism too, all swooping cranes and tracks exactly in time to the characters' movements, in and out of rooms, through corridors and down streets, moving up towards the sky for the perfect landing. But all the motion ends up constricting rather than opening up the characters' movements; there's no spontaneity in the blocking, no freedom in the steps. It's all hard and fast. There's no grace.
It's for the better, I guess; remove the formal showiness and there'd be no cover for the mediocre dancing, set to a mediocre jazz score. I mean, seriously, this is some straight out of undergraduate dramatic arts program, off Broadway, Michael Buble material. And I know that makes me sound like an elitist, but there's the rub: Chazelle can't keep making movies about artistic excellence if he's going to keep filling them with subpar artistry.
And what is Chazelle if not an elitist, railing against the gluten-free pastry consumers of the world and the strict enforcers of tacky setlists (in what world does Chazelle live in that a high end restaurant in LA wouldn't want their performer playing free jazz?). He needs to set up strawmen for his protagonists to come in conflict with because he doesn't trust the audience to grasp that his leads are superior simply from watching them, and he's right. He needs antagonists to stack them up against, to prove their superiority. This tendency culminates in the shockingly awful John Legend subplot, in which Chazelle focuses his ire on the introduction of synths and pop into jazz music (because this is the 1980s, apparently). But the joke's on him: there's no difference in quality between Legend's pop concert extravaganza and the music proper in the film. Mediocre is mediocre, with synths or without.