Rotten Tomatoes‘ Consensus:
“In Cuaron’s hands, Azkaban has emotional depth to go along with the technical wizardry.”
Harry Potter and the Prisoner of Azkaban changed the game for the Harry Potter franchise. It was the biggest jump in regards to the maturity of the actors, the tone of the series, and the start of the major plot devices that would define the Harry Potter franchise. All of these were handled well in a film that drastically improved on the shortcomings of Chamber of Secrets.
This was the first film where fans really got a taste of selective inclusion. Parts of the novel were intentionally left out because of the way the first two films dragged at times. This, at the time was seen as a negative thing by the fans, but as the films went on, the decision was praised as a necessary loss. Cutting content was a good and bad thing to do, and overall helped make the franchise better.
Prisoner brought together a set of great additions to help make the franchise better exponentially. Adding David Thewlis as Remus Lupin and Gary Oldman as Sirius Black was a huge step forward, and Michael Gambon did a good job not derailing the franchise after taking over as Dumbledore following Richard Harris’ untimely passing.