A good man, with flaws. To say that he was an authoritarian is unfair. He continued the reforms of Vatican II, and the church did not become notably less centralized during his pontificate. He has been criticized for not advocating "progressive" policies (although he always advocated left-of-center economics but as Pontiff his job was to head a church not engage in politics based what was current "en vogue."
After seeing the Nazis and then the Communists persecute the Church in his native Poland he was the ideal man to head the Church at a critical time during the Cold War. His actions helped herald in the collapse of the iron curtain and the formation of a democratic eastern Europe. His experiences with during war-time and post-war time persecutions led him to raise of the opposition of the death penalty on the grounds that it was unnecessary. This was debated. The finances of the Vatican were restructured by then Cardinal Joseph Ratizinger and are in much better shape then when JPII took power, although the American church's finances are a mess due to lawsuits due to reasons that are about to be stated.
It must be stated that his experiences became a severe weakness (as well as his age) due to as he was unable to deal with a scandal involving a massive amount of pedophile priests that have been confirmed to have molested children. The sheer awfulness of these crimes cannot be underestimated. It is apparent that JPII was not prepared for this crisis. During the Cold War, and WWII Communists and Nazi officials would accuse innocent priests of similar charges for grounds of arrest during their persecutions and JPII was suspicious of such charges as Pope. The inability of JPII to think beyond his own experiences in this case resulted in serious blunder, to put in mildly. In addition, the independence of the American church (as well as the Jesuits), based purely upon it's financial resources, can be criticized.