I think the most important issue in modern governance that nobody ever talks about is the tendency for the number of laws and the size of the legal code to monotonically grow towards infinity
More importantly: this is both to be expected and rather benign. It's expected because regulation simply grows with the complexity of society, which is increasing at a similar or even larger pace. Most of our wealth is due to specialisation and research. And with the benefits of, say, flying cars, comes the need to establish rules.
It's also benign because almost nothing of it will ever concern you, or any other specific individual. You can fly your car without knowing the crash test procedures for it. They are relevant only if you are building flying cars. In that case, you do have to familiarise yourself with the rules, but that is a task of the same magnitude as it was with existing regulation for (regular) cars, which no longer concern you.
And I would be highly skeptical that it would ever approach a finite value, I mean, why would it? What is the incentive for politicians to just stop making laws once they reach a certain threshold?
Here is a quick chart I found with google that indicates, at least as the American federal govt is concerned, the growth is essentially linear: https://regulatorystudies.columbian.gwu.edu/sites/g/files/za...
https://fee.org/articles/idaho-repealed-its-entire-regulator...
> [I] never saw so many alligator shoes and $600 suits as when some agency is up for sunset review.
Source: https://www.thefreelibrary.com/Is+the+sun+setting+on+the+Tex...
That suggests a more general downside from sunsetting--it increases opportunities for lobbying. Worse, it benefits long-term preparation and strategy, which will favor monied interest groups and lobbyists especially. Which is similar to the downsides of term limits, which effectively shifts power to those behind the scenes--e.g. political operators, party bosses--rather than to the electorate. If you make serving in an office a literal revolving door, you empower those positioned to line people up at the door. Likewise, if you make lawmaking a process of continually rehashing old compromises, you empower those playing the long game.