If you've got a statute like "no vehicles in the park," the fundamental issue is that you have to interpret "what is meant by 'vehicle'?" and no legal drafting is going to be good enough to actually cover all the possible cases well enough. The main difference between a common law and a civil law system here is that in a common law system, you have to cite the previous similar cases (because precedent is binding) whereas in a civil law system, you're merely using those previous similar cases as persuasive evidence. At the end of the day, it boils down to arguing for your interpretation.
And in my experience working on language standardization (which is closer to a civil law system than a common law system), it's fairly often that I have to resort to looking up not just when a change in the text occurred, but dive deep into the discussions of the paper proposing the change to understand what the committee thought it was doing with the change. The complexity of law is fairly similar--the changes to the law themselves often require understanding the legislative and interpretative history of the law to understand what the intent of the drafter was to be able to rule on how the law is extended to an unanticipated scenario.
If you want to know the literal text (that may or may not be enforceable), then sure a plain text diff is sufficient to know that nothing at all has changed about federal communication laws since this section was last amended in 2002. But if you want to know what the actual law is, you definitely need more than just a text diff.