The Prisoner of Azkaban is a fantastic story that also made significant contributions to the rest of the series movie wise. I believe that the first two films were too similar to the book in the sense that they didn't adapt well to the screen. The Sorcerer's Stone is more excusable considering it serves more as an introduction to the entire world of magic and such. But the first two films really dragged on as it tried to squeeze as much of the books as it could into the screen. After re-watching the first two, there also seemed to be too many moments where there was a pause for dramatic, suspenseful effect. I don't know if this can all be blamed on director Chris Columbus, but the movie series definitely took a different direction (pun intended) when Alfonso Cuarón took over for the third film. It flowed very smoothly and the paced was picked up a little. I'm not upset about anything specific that was left out because it needs to happen for the film to work. However, minor details were the only thing really missing and the film length was cut down from the first two by about 15 minutes, even though the third book is significantly longer than the first two.
There is one other thing that always bothered me about the first two films. I wouldn't know who to place blame on really, and I never noticed it until the third because it was so different, but who the hell designed the Hogwarts grounds in the first two films? Not the castle itself, but the surrounding area. Anyone else notice that the scenes taking place outside in the first films were shot on entirely flat ground on clear days or nights? Way to stimulate my visual senses. Beginning with the third film, the grounds designs were changed dramatically. There were cliffs and mountains/hills/terrain and bridges and actual scenery that suddenly appeared in Prisoner of Azkaban that were largely absent from the previous installments. They never were part of any scenes, more for just pull-back shots and scene changes. Before, Hogwarts was there, and then there were surroundings. The third film showed Hogwarts as a place built into its surroundings rather than a place that existed alongside them. Perhaps the most noticeable difference was the location of the Whomping Willow, which characteristically appeared on its own on a flat patch of grass outside the castle in the second film. The next film had it along the edge of a hillside, outside the walls of the castle, and actually seeming like part of the scenery. With that inclusion, along with the overall darker tones of Dementors and Werewolves made the third film a clear visual upgrade. The template for the grounds has been used in every Potter film since, which is nice to see, but it also hasn't been exceeded, at least not obviously.
I remember a few years ago when Facebook was still a place for only people who had a college e-mail account. There was I group I saw that proclaimed that Richard Harris was a much better Dumbledore than Michael Gambon. These people are morons. I'm not glad that Richard Harris had to pass away for Gambon to land the part, but as the books progressed it became increasingly clear that Dumbledore was a commanding force to be reckoned with, and Harris' portrayal was one that was too grandfatherly to be that force. I won't claim that this recasting, which was clearly not intended, made this movie better, but Gambon has been a better Dumbledore. In fact, as far as role casting goes, whoever is in charge of it in these movies receives as A. Whether or not the actors chosen fit the exact physical description of their characters in the book (ahem, Alan Rickman), they have played their parts excellently. Helen Bonham Carter as Bellatrix Lestrange? Beautiful. Kenneth Branagh as Gilderoy Lockhart? Delightful. But my personal favorite is Gary Oldman as Sirius Black, who makes his first appearance in the series in Prisoner of Azkaban. The man who would become Commissioner Gordon in the new Batman series, and the man who foolishly tried to take over a plane that Harrison Ford was on plays a damn good Sirius Black, which was essential for the best story of the whole series. This doesn't take away from the great casting in other films, but rather bolsters Prisoner of Azakaban's credentials.
I've mostly pointed out the flaws of the first films, and it is true that the more recent movies are generally better. However I take a few issues with the fourth and the sixth and most recent film. Goblet of Fire was probably the most anticipated. A Triwizard Tournament, the return of Voldemort and the Death Eaters. I don't think it completely flopped, but there was a lot missing. They had even thought of splitting this movie into two like the final book, but felt it didn't fit. It's not that specific plot elements were missing, as their inclusion would've created a Return of the King-ending-type feeling for 3+ hours, it was a matter of what was included compared to what wasn't. The addition of Barty Crouch Jr. into the opening scene actually eliminated the twist at the end, and could've been accomplished more subtilely otherwise. And the buildup to the Quidditch World Cup yet its exclusion in film probably pissed off everyone who has ever read the book, including me, and it quite possibly could've been the most anticipated scene in the movie from book fans. It could be compared with Spiderman 3, a film that was solid, but tried to put too much into the film, but found it impossible to leave things out.
With the sixth and most recent film, I felt it was rather anti-climactic in multiple regards. I understand the exclusion of a battle scene at the castle to avoid repetitiveness in the fifth and the final films, but the confrontation between Harry and Snape at the end fizzled. I don't know whether to put blame on director David Yates or Rickman but Snape should have been way more passionately outraged at Harry using his homemade spells, like the book. The love story between Harry and Ginny was also lacking. What was in the book a surprising, somewhat climactic embrace after a Quidditch Cup victory was completely changed into a half kiss, and the story wasn't picked up and just presumed afterward. Not such a big deal had there also not been the buildup. Most everything else missing or lacking in the film can be attributed to it being a "transitional" film.
I actually found nothing wrong with the fifth film, which I watched again recently before the sixth appeared in theaters. I think that Order of the Phoenix is actually a close second to Prison of Azkaban in terms of its presentation on film. More excellent casting (Imelda Staunton as Dolores Umbridge), and a great first big good vs. evil magic fight scene, but I always felt that Prisoner of Azkaban was a better story. They were both more darker tones with a light-at-the-end-of-the-tunnel endings. However, Prisoner of Azkaban contains one of my favorite scenes in all the cinema I've seen, when Harry takes Buckbeak for a cruise over the lake. It's hard not to enjoy that scene. The story, not that scene, gives it the edge, but it's nice to have a memorable movie moment, something I don't think was quite given in Order of the Phoenix. In conclusion, Prisoner of Azkaban ftw.