The answer regarding near perfection was answered before the Constitution was written! NO! After all they were basically the same men who wrote The Articles of Confederation.
Were they basically the same men? This was the committee who made the Articles of Confederation (each from a different state).
John Dickinson (Pennsylvania)
Samuel Adams (Massachusetts)
Josiah Bartlett (New Hampshire)
Button Gwinnett (Georgia)
Joseph Hewes (North Carolina)
Stephen Hopkins (Rhode Island)
Robert R. Livingston (New York)
Thomas McKean (Delaware)
Thomas Nelson (Virginia)
Edward Rutledge (South Carolina)
Roger Sherman (Connecticut)
Thomas Stone (Maryland)
Francis Hopkinson (New Jersey)
Of this group, the only ones who I believe were at the Constitution Convention (which had 55 attendees) were John Dickinson and Roger Sherman. That means that 53 out of the 55 delegates to the Constitutional Convention were uninvolved with writing the Articles of Confederation, including the one who was probably the most important of them all in writing the Constitution, James Madison. There doesn't seem to be much overlap between the Articles and Constitution in terms of who wrote them.
But they did a lot better than the people nit picking on this thread would do, even with the advantage of hindsight.
I would generally agree, but I still think failing to anticipate the effects of political parties was a major oversight.