The) Constitution was far more than "amending the Articles of Confederation."
I think most historians would agree that the attendees to the Constitutional Convention understood that the Articles would need to be completely replaced.
In point of fact, the Articles were not completely replaced. The two constitutions have a lot more in common than they have differences. They were both attempts to fulfill the principles of the same Declaration. And both do.
Which kind of brings me around (though not in revolution): if one is to estimate the so-called liberalism and conservatism of these two governmental designs, doesn't it makes sense to start with the Declaration principles that the designs were intended to fulfill?