No other possibility
Just because you wish it doesn't make it so.
The Founders could have easily specified that; they didn't.
“The Founders could have easily specified that; they didn’t.”
They did so by adopting Natural Law and the Law of Nations in the Constitution, and they in turn give effect to the common law in which natural born citizenship is adjudicated. The Founders also specified what forms of citizenship were not natural born citizenship, and that included any person born abroad, with or without U.S. citizen parents.
They did specifiy that. That is what natural born citizen means.
Born here of citizen parents.