I have often wished that the U.S. was more “united” than it is “states.” A republic succeeds or fails depending on the people running it. That’s the case for any form of government. A dictatorship would be very efficient, effective, and humane with the perfect person in charge. It can also be Hitler.
The U.S. has just over five times the population of France so there are also issues of scale. Sometimes it’s good to have 50 states so you can escape one state’s insanity and go to a state more suited to your needs.
My expertise is not social or governmental science. Reason is about all I bring to the table. And since religion is often the opposite of reason, religion and government are a recipe for disaster. I look less at the form of government and more at who runs it.