One criticism of the constitutional amendment process is that it is almost impossible to get proposed amendments out of Congress. In fact, Politico reports that University of Virginia Professor Larry Sabato described Congress as "a burial ground" for amendments.
In the Politico interview, Professor Sabato reports that more than 9,000 amendments have been proposed to Congress, but only a few dozen were sent to the states. Of these, far fewer became amendments. While it may not be obvious from his book, "A More Perfect Constitution," Politico indicates the professor prefers the state-initiated Constitutional Convention method rather than starting with Congress.