In the course of Dantes' revenge plot against Mondego, Fernand is publicly vilified and humiliated, and Mercedes and her son Albert head to far-off lands where their names and pasts will not be known and they can begin new lives, away from the shame brought to them by Fernand Mondego as their husband and father. Both Mercedes and Albert are basically good people, and their shame at Fernand's actions shows this. Yet the fact that they must leave to start new lives is a very harsh punishment, and it is visited upon them through no fault of their own. Dumas seems to be making a subtle point about revenge and the fallout of any action that harms another person, even -- or perhaps especially -- if the harm is only done to their reputation. Regardless of the point he is making in the novel, however, it is clear that the world is not simple, and that good people must suffer, too. In the movie, however, tings end up drastically different for Mercedes and her son Albert, as well as for Dantes himself. Fernand Mondego is still shamed by some of is pas actions, but rather than flee Mercedes tells Dantes something very important -- Albert is actually Dantes' son, and the only reason Mercedes married Mondego was because she thought Dantes had died shortly after being imprisoned. This allows Dantes and Mercedes to form a new relationship, and Dantes is able to know Albert as his son. The movie ends with this new happy family starting a calmer life together, something that would have been utterly impossible in the book. In this way, the good aren't punished and in fact tings end up almost as happy -- perhaps happier, due to Dantes' riches -- as they would have had Dantes never been imprisoned. Balance is restored more effectively in the movie than it is in the book, making the story sharper.

One of the most interesting characters in the novel is Villefort, the inspector who falsely condemns Dantes for his own personal and political motives. Dantes plot to get revenge on Villefort is one...

This novel does an excellent job of making him a well-rounded character; he comes across as a basically good man who did several horrible things out of desperation, and who ultimately is taken over by his internal guilt. Though there is some element of this in the 2002 film version, it is again more black-and-white when showing his character and his punishment. The only crime in the movie that Villefort is shown to be guilty of is imprisoning Dantes in exchange for the murder of his own father, but he is generally seen in a much more negative light than that in which he is presented in the novel. His eventual arrest signals that he is not at all good, and could never have hoped for a kinder fate.
Films simply cannot be as complex as many novels and still retain the power of emotional and dramatic sway over their audiences. If all of the character and plot twists of Dumas' the Count of Monte Cristo had been included in the film, it would have taken eight hours (or longer) to watch and would have been immensely boring and hard to follow. Even the book can be difficult to follow at times, but with careful consideration and the ability to take one's time, the reader is still able to enjoy the story. In a film, however, the pace has to remain relatively fast in order to keep everyone's interest. This film version does an excellent job of keeping the original impact while changing the story.