Last time (
https://www.alternatehistory.com/discussion/showthread.php?t=255111) the general consensus was that a Franklin presidency would be extremely unlikely on account of his age.
By the time Washington ascended the Presidency Benjamin Franklin was unable to walk because of severe gout, suffered from syphilis, was likely going senile and blind. He was so infirm that he had to be carried into the Constitutional Convention on a sedan chair. Robert Morris complains Franklin, as President of Pennsylvania, left all his responsibilities to the state General Assembly. This is hardly a good track record.
Assuming Franklin miraculously manages to survive until 1792 he will not be doing any governing. What we will see is a United States where the President is more a figurehead and rubber stamp to powerful Congressional leadership. There will be nothing "policy wise".
To have something like a Franklin presidency, it seems to me that you would need either a much earlier revolution, which would butterfly everything beyond recognition; or, with a later POD, create a situation in which some protege or intellectual successor of Franklin is elected president. Some sort of posthumous movement based on his works would probably be the best way for Franklin's personal philosophy to have a big influence on the early development of the United States.
As a POD, I would suggest the early death of Jefferson, leading American republicanism to develop into a different form, with Franklin as its primary ideological source. He is remembered as the towering "idea man" of the revolution, and the major connection between the Revolution and the Enlightenment. He exerts far more influence on the country's foundational texts. This tilts the scale in favor of a more whiggish, urban, public-spirited and politically centralized nation, as opposed to Jefferson's agrarian autarkic model.