Growing up in a culture similar to Japan, where the expectations placed on kids are similar to what's seen in the video, I can say there are pro's and con's.

The pro's are kids learn faster when it comes to STEM subjects, where brute hard-work and repetition pays off (because until you go to university, you're pretty much limited to learning widely-accepted truths, which just needs to be understood and remembered).

The con's are the same work ethics and discipline applied to creative subjects doesn't necessarily work. Yes - you need practice to be good at playing musical instruments, but you also need to have the space to "mess around" and have some fun. In the video, the girl was obviously enjoying her time playing the cymbal, only to be told by her music teacher to be serious and not mess around. It really hurt me to see her creativity and happiness smothered by that killjoy.

Watching the Op-Doc reminds me of the book Totto-chan, the Little Girl at the Window (窓ぎわのトットちゃん) (there's also a movie) where it showed that some "problematic" children are really just curious children who didn't get their curiosity satisfied.