So your position is that the Founding Fathers f’d up writing the Constitution but these guys 80+ years fixed it, right?
Why are you putting words in my mouth?
The Founders chose not to provide an explicit definition of "natural born citizen" in the Constitution. Lacking such a definition, the recourse for understanding the term is to refer to the common law.
Had this been a civil law system, the lack of an explicit definition *would* have been an "f up", to use your phrase.
But they didn't; as such, in the course of future disputes, recourse was then had to the common law, which was then built up with each subsequent court case related to citizenship. After any constitutional amendments (such as the 14th Amendment), future court cases were then reinterpreted in light of changes to the supreme law of the land.
If the Founders had wanted to sever us from the common law entirely, they would have said so. But on the contrary, the extant documents of the day indicate that it was retained, overwritten only by subsequent laws and statutes to the contrary.