Regardless of whether or not one likes the music itself, 'Dangerous' set the blueprint for all pop music thereafter both sonically and visually. An experimental pop album with varied styles and genres like (miss)understood could have never existed without 'Dangerous.' The album was also brilliantly engineered and greatly emphasized the importance of mixing and mastering in pop music.
Susan Fast is writing a
book about the album.
Anyway, I think MJ and Ayu have more in common in the sense that they're not so obsessed with being perceived as trendy per se, but more concerned with staying true to themselves and making music that reflects that. Madonna, on the other hand, just does whatever she thinks is in vogue at the moment and creates an entire era based off that one sound/style. Her last few albums particularly show that she's suffering from an identity crisis and that there's no real sense of continuity in her work at all.