Why did they decide to write the US Constitution rather than simply revising the Articles of Confederation?

The Articles provided a weak central government, where the government did not have to power to tax. It also provided little means of revision. The Constitution, on the other hand, establishes the 3 branches, and more importantly, a constitutional government. The fundamentals of a constitutional gov’t include majority rule and minority rights, limited gov’t, institutional and procedural limitations on power including separation of powers, checks and balances, and due process of law.