Well, the founders of Sibelius created another music notation software called Dorico[1].
Is Dorico's UI more consistent? Does it address many of the issues of this video's criticism?
Or put another way, does being a green-field software project allow the freedom to create a sane UI? Or did it have to deliberately copy may of Sibelius' faults so migrating users can quickly get up to speed with Dorico? (Analogous to MS Excel copying Lotus 123 buggy leap year of 1900 to be more compatible.)
EDIT -- just noticed same uploader also made a 1 hour video about Dorico[2] but not sure if answers my questions.