I played the game and despite not being a deep character at all, I think he was handled really well in the story. The guy is a threat to all of the Japan and game really makes you feel that, even at the design of his palace. While he may be a very simple villain, he really manages to make us hate him and fill our soul with rebellion, which is exactly what game wants you to have.
Also, his boss fight is chilling, with "Rivers in the Desert" playing in the back, it's impossible to not get excited for me lol.