Haven't watched the video, but I agree with the title at least. Persona 5's writing is the laziest yet, the last quarter of the game is a fucking mess that reeks of rushed development. The OST is good but noticeably lacking in variety. Rivers in the Desert is good, but over the same endgame span, Persona 4 had New World Fool, The Almighty, Fog, and Genesis as endgame boss themes while Persona 5 used Rivers in the Desert three times and Yaldabaoth once. S. Links are all homogenized and go too hard on the themes of corrupt authority to the point where every rank 8 and 9, for everyone outside of your party, hits the exact same story beats. Persona balance is a mess. The characters are flatter than ever. Every time it looks like the game is going to have a swerve that raises the stakes it turns out to be a fakeout.
3 and 4 weren't perfect, but they were also tighter productions that didn't feel unfinished and were mostly fleshed out and didn't leave you wanting too much more. Persona 5 had a notably troubled development cycle and it shows.