> It makes perfect sense to believe that natural language interpreted by an LLM is the next step in this evolution.

Which one? Most languages are full of imprecision and change over time. So which one would be best for giving instructions to the machines?

In the scheme described in the article the main input for AI would be the tests. If we are testing code outputs (and why not) the input then must be in a programming language.

Specifications need to be unambiguous but Natural Language is often ambiguous.