Actually the children of both military and diplomats serving temporarily outside the country are, by section 217 (section 212 is where the NBC criterial comes from), Book I of Vattel's Law of Nations, are deemed to meet the "born in the country" criteria.
Section 217 Children born in the armies of the state.
For the same reasons also, children born out of the country, in the armies of the state, or in the house of its minister at a foreign court, are reputed born in the country; for a citizen who is absent with his family, on the service of the state, but still dependent on it, and subject to its jurisdiction, cannot be considered as having quitted its territory.
Suppose an envoy, a citizen at the ratification, had been in England, where a child was born. For the next fifteen years the child was educated in England, returning to the U.S. in 1812 (perhaps on The Venus). He continued his education and became a presidential candidate twenty years later. Did our founders want to vouch that his formative years in England didn't make him long for the autocratic structure and apparent civility of The Crown?
I believe the definition stated by Marshall was intended. Had the legislature wanted to amend it they would have proposed that. I suspect, from The 1790 Act, that there was sentiment to amend it, but with the vast majority included in the natural born citizen category, why take a chance? Our strongest branch of government was the people's house, because it was the branch closest to citizens. I doubt that the house would have approved an amendment to enable foreign born citizens to hold our highest office. I do understand the sentiment. It would have validated McCain, but certainly not Obama.