No Sympathy for Pu Yi
Admittedly, I don't know much about the history or politics of the events in the film, so I won't speak on his actions as a leader.
Pu Yi was an entitled jerk who was terrible to everyone except his Scottish tutor, until almost the end of his life.
Prison forced him to lose his superiority complex, so he never reformed of his own will. The fact that he was deposed and imprisoned but still demanded his servant/cell mate to cater to his needs speaks to his pervasive sense of entitlement.
It can be argued that because the people around him always allowed him to do whatever he wanted, he never learned how to treat people well, but he was almost sociopathically cruel--he made that one eunuch drink ink just to show his brother that he was omnipotent, he killed that mouse because he was mad they wouldn't open the door, he never tried to help his wife with her opium addiction, just refused to be intimate with her, he paid no attention to his second consort until she decided to leave, then he refused to separate from her.
He only cared about himself and I think he deserved much worse punishment for everything that happened to the people connected to him as a result of selfish actions.