Regarding prophecies and predictions, rare is the prophet who say the future is inevitable. People who have the ability to see into the future serve as emissaries, warning of what might be, not what will become. Had people took the prophets and predictors seriously, horrors would not heave come to pass.
I wouldn't knock Nostradamus. He was a good Christian who it seems got his amazing gift as a blessing from God. The reason he became quite inaccurate in the later parts of his predictions is because we prevented the future from happening. HE said himself that these are not things that will be but things that may.
With St. Malachai, so far his predictions have been spot on. It is up to us to ensure that this world will have many good Popes for centuries to come by squashing the socialist and jihadi scourge. The same for the Revelations in the New Testament. We must make sure that the anti-Christ and Dragon will never come to be.