Initial issue with Count of Monte Cristo: caricatures instead of characters.
Enter Edmond Dantes, handsome, charismatic, beloved by boss, parent, and fiancee. He is a good guy. As spelled out in capital letters by Dumas before page two of the book.
Then the enemies come in: Danglars, jealous of Dantes's recent promotion to captain; Fernand, jealous of Mercedes Love for the Hero. And some random neighbor who is unsavory in general.
In other words, there's not a whole lotta depth to these guys. They are good or they are evil. The characters that come up will either help the Hero or try to destroy him--part of the novel's lengthiness is the fact that so many people are jealous of this upstanding gentleman, and the lengths they go to bring to him down are extreme, to say the least.
I realize that Count is kind of dated. Some of the reading issues are with me. After reading so many writing books and reading so many contemporary authors who follow the new, established rules of writing fiction (with perhaps the notable exception of Palahniuk...whose extremeness stretches those a bit) I need to stop looking for the 'psychology' of the character and just enjoy the ripping ride Dumas has in store.
At 1200ish pages, there's one hell of a plot going on. Each character has their own motivation, which is a bonus in my opinion. Far too often the characters just go through the motions. But each one is acting on their own principles and I've gotta give Dumas credit for that.
Now if only I can keep on turning the pages. One page at a time right?