I like the idea that a piece of legislation should come with concrete criteria for its own evaluation. That would be like falsifying scientific theories: "This theory will be falsified if such-and-such a phenomenon is observed." "This law will be repealed in X years if it turns out to have such-and-such an effect on the economy."

Unfortunately, laws can rarely be evaluated in isolation, but only against a wide range of other laws and actual circumstances that constantly shift. It's hard enough to come up with definite criteria for falsifying an advanced scientific theory. It will be nearly impossible to do that with laws, not to mention it's too easy to dispute whether the criteria have been met.