Bookmark and thanks Alex.
You will not hear me be too forceful in defense of many of these pontiffs. There was some good that came from some of them, but largely, the influence of the secular power they wielded detracted from their legitimate spiritual role.
Take Leo X, for example. Even a source like the Catholic Encyclopedia says:
The only possible verdict on the pontificate of Leo X is that it was unfortunate for the Church. Sigismondo Tizio, whose devotion to the Holy See is undoubted, writes truthfully: "In the general opinion it was injurious to the Church that her Head should delight in plays, music, the chase and nonsense, instead of paying serious attention to the needs of his flock and mourning over their misfortunes". Von Reumont says pertinently=;"Leo X is in great measure to blame for the fact that faith in the integrity and merit of the papacy, in its moral and regenerating powers, and even in its good intentions, should have sunk so low that men could declare extinct the old true spirit of the Church."
With other popes, it gives the good, the bad, and the ugly. (If anybody is interested, look at this link for a list of popes and links to their bios)
But I do agree with the basic premise of the article, though: Luther likely would have remained a humble priest had these pontiffs executed their offices more faithfully.