'The law' is open to judicial and legal interpretation. There isn't always a single 'the law' to interpret in complex cases. While there are many, many rules, they are not as simple as code and they rely on deep layers of precedent. Common law is made up of case history more than statute.

> One of the upsides of "code is law" in that respect is being able to provide a clear statement of what the law says

No, "code is law" in fact always ignored what any actual law said, in favour of framing everything as a sort of contract, regardless of whether said contract was actually fair or legal, and it removed the human factor from the whole equation. It was a basic failure to understand law.