I'm not sure coding has ever been the hard part. Hard part (to me) has always been to be smart enough to know what, exactly, I (or somebody else) want. Or has someone heard of a case when someone says something like "These requirements are perfectly clear and unambiguous and do not have any undefined edge/corner cases. But implementing that is still really hard, much harder than what producing this unicorn requirements spec was"?

But they already know what they want, they have it. Rewriting it to be more efficient and less buggy should be the lowly coding that is supposed to be solved