I've never really understood this argument, because it assumes that if a bad law is enacted, there is no recourse. In a system where a law could be passed in a few days, wouldn't it also be able to be repealed in a few days? Why not have formally-provisional laws: "try it, see if we like it, throw it out if it didn't work?"
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Or, even, (tangent incoming): "try a new law on some [randomly-selected] subset of the nation at a time, record metrics, see whether the experimental population or the control population are doing better" -- A/B test the nation?
That's theoretically what the whole system of state law was for--let each state experiment with its own law--but this has been less and less tenable for generating scientifically-valid data as it has gone on, as the policies states have enacted have caused them to diverge (where instead "good" policies were supposed to be converged to as other states copied them, and "bad" policies eliminated from the "gene pool"), and has caused people who agreed with each policy to move there and people who disagreed to leave. Now doing an "experiment" with a new law in one state will tell you next-to-nothing about how another state would react to it.
Now (or soon), we can efficiently enforce [some forms of] law at the individual level--just mark people in a database saying "this person is legally allowed to smoke marijuana" where a cop can look it up from the console in their car, or "this person will be charged a VAT instead of an income tax" where the credit and EFTPOS networks can look it up and handle it. Law doesn't have to be all-or-nothing. But this is, of course, a silly pipe-dream to apply to a current, entrenched nation. It'll probably be one of those things some charter city could run with, though.