He was the last truly catholic pope, but he certainly was very far from being a great one.
THIS^^^. He was undoubtedly one of the worst legitimate popes in history. He was the watershed that led directly to Vatican II.
1) opened the door to evolution
2) opened the door to NFP as Catholic birth control
3) started the first ecuмenical meetings
4) enabled Bugnini to begin his liturgical experimentations
5) did not defend Father Feeney against Cardinal Cushing's heresy, and so failed to defend EENS dogma, which led to Vatican II. He had the opportunity to stand up for and reaffirm EENS in a way that would have precluded Vatican II
6) appointed, during his long reign, the vast majority of bishops who would later bring us Vatican II