A unanimous vote was required to make any changes to the Articles.
Not all of the states were in agreement that changes needed to be made and therefore adjusting the Articles would be difficult.
Each state wanted sovereignty and the changes needed in the Articles would take away sovereignty. The Articles required a unanimous vote and coming off of a war and trying to establish themselves smaller states were less willing to make changes. Even at the end of the Constitutional process, Rhode Island still did not agree with the changes or ratification.