Actually reading collections by Madison, Hamilton, Jefferson etc begin to feel like work to most of us, little too high brow, so we don't do it and are ignorant. There has never been a set of men of that intellect converge in history though so we should.
These folks, each of them, had in mind a basic concept they sought to bring forth. Each could 'bend' only so much in order to bring about a viable entity that would insure that their State's needs would be firmly established.
The beauty of their work is in how they managed to accomplish anything so firm yet loose, so specific yet vague and have its stability universally (among the 13) supported so to enable subsequent generations to find their needs met as they and their environment ebbed and flowed regardless of the climate.
The words of Jefferson's Virginia Bill of Rights are not verbatim found in the US Bill of Rights but I think that work is by far the reason the folks were able to agree to agree... It is a fundamentally sound bit of understanding of then and today.
I couldn't begin to evaluate the intellect of Madison, Hamilton, Adams or any of them based on some criteria in place during their time... What one can do, I think, is to look at the product of their endeavors and interpolate back to their brain power and ability to bring forth an enduring form of Government that enables even the most radical opponents to have a forum to disagree.