Vattel only described what was already in practice in the 18th Century and earlier centuries. Killing the messenger in the form of Vattel does nothing whatsoever to change the meaning of natural born citizen as it was practiced in the periods leading up to the Constitutional Convention adn the adoption of the Constitution.
Right. Practices like the impeachment of Charles I. Thwop! Roll! By Act of Parliament. LOL!
The United States was a new idea. It was not about perpetuating old, inferior European traditions.