Is it wrong that what I’m taking from this is that things ran much more smoothly when leaders focused on leadership and things went to hell after they got their hands on legislature?
How do you define leadership without including any legislative responsibilities?
It isn’t exactly difficult. The state does more than just writing laws, you know.
This is true. However, it doesn’t change that from the time the Roman Empire collapsed to the restoration of the Monarchy after the English Civil war the people of Great Britain were usually at war with either the continental Europeans or each other. So at least as far as England is concerned, things did the opposite of running smoothly before their leaders became enthusiastic legislators.
This depends in part on what is meant by “more smoothly” – are things running more smoothly, for example, when a system takes no notice of the question of motive, and treats one child accidentally killing another the same as deliberate murder by an adult?
More broadly I challenge the idea that simpler law adheres more to “common sense”, to the extent that is even meaningful – judicial innovation comes about because existing law is nonsensical.