When is a dictator a bad dictator is a matter of opinion. As for
division of power, China has division of power since Sui.
Hilter's dictatorship was welcomed by the Germans. Not many at that time
considered a bad dictator. Concerning the US, Barbara W Tuchman had
suggested long ago that US presidency should be removed.
Of course, Hilter and his Germany did not last and the US is still the
world power. So the issue is not how a leader exercise his power but the
policy push forward and results achieved by his power.
Anyway, democracy is about the people, not how top leaders exercising
their power.
America's problem is that people are mostly out of the loop except
ritualistic voting.