Well, I finally saw Spiderman 3; it's not as bad as people claimed. However, I do understand why people would say so and how this movie paled in comparison to the first one.
Spiderman 3 had inconsistent pacing, undefined tone, and weak overall characterization.
This movie had inconsistent pacing and at times it felt choppy. A better editing could have tightened the movie and make it stronger (cut out the extra/unnecessary scenes, have a better sequencing of events). Usually in comic genre, this choppiness is understandable (McCloud's theory- the reader participates and imagines the ongoings in the 'gutter'- make things happen, the reader is like the projector that makes the picture move) but in the movie genre, smooth flow and transition are necessary (the choppiness is more obvious because it's immediate, the audience instead of the reader is receiving information through sight instead of letter and symbols which need to be deciphered).
And the miracle of being saved at the last minute, the villain, who never gets killed and always finds a way to come back are all expected in comics but in movies, if one tries to make exactly the same as the comic book it'll be like one of those read-along dvds, one might as well adapt it to the e-book/graphic novel format, why even bother taking advantage of the film medium? The audience might think that the story is over because the villain is killed and then another villain rises, then half an hour later, the first villain is resurrected or loses his memory. The multiple storylines in Spiderman 3 were disruptive.
The tone of this movie is undefined. In Spiderman 1, the tone was consistently dark with a sprinkle of humor (which surprised me especially since Spiderman is a masked hero wearing royal blue and crimson tights- in my mind I'm thinking about Wolverine's comment in the X-men movie about yellow spandex). However in Spiderman 3 it wasn't as dark as I thought it was going to be (I like the concept of the "symbiosis" feeding off hatred and turning the Spiderman suit into black but this wasn't consistent- with better editing, the movie could have focused on this plot as the main arch, and added on to it instead of making it as one of the little plots). The beauty of the first movie is its credibility (its comicness and campiness are not so blatant). The campiness- forget acting, it's all about miming and exaggeration, which do not work in the film medium- it looks fake. It's not the same in paper (the frozen exaggerated moments are apt to spur the reader to imagine the rest)...
One moment, Jamison, the stressed editor, provides comic relief and then suddenly Mary Jane (MJ) is jealous of her boyfriend, Peter. Later on the angry Peter is saying cheesy one-liners wrought with sexual puns and then he's a slimeball checking out every girl in Manhattan, then he's tap dancing with another girl to make MJ more jealous. The comic and tragic moments are not balance (there's no smooth transition from one to the other). The tone is like Harry's character (Peter's bestfirend, who's out to get him for "killing" his father)- it's very schizo.
Because the movie tried to deal with every character, the characterization became weak. The first movie is mainly about Peter Parker and everybody else are supporting actors. In this movie, they tried to make MJ complex by showing her insecurities and jealous tendency, Harry, the schizo, just wants to be loved by his father (he's a rich brat who can paint, cook, and play sports)...the good characters are not as bad as the villains, talk about arch enemies who literally have really archy eyebrows...how about the Sandman character?, who's only hurting people and robbing banks in order to raise enough money for his daughter's operation, then later after all the damage is done then he starts questioning his morals and asks for forgiveness... whose idea was to cast a newscaster/reporter with a British accent working in N.Y. television?
Stan Lee's cameo was as unnatural as ever, the audience is already aware of the movie's comic nature (the magic and illusion gone- I know it's a movie, but it should also lure me in its world).
Spiderman 3 can't stand on it's own (not like the first one), it needs the first two for the audience to understand the growth and maturation of Peter Parker. Having said this, the director/producers have no excuse of disregarding the factors that made the first one successful for the sake of doing something novel to the final installment of the Spiderman trilogy. The factors, which made the first one successful, include great integration and balance from the comic medium to film (importance of flow, pacing, centralized/main plot, strong believable characters). This movie tried to accomplish too much in a "short" time. Instead of making a bang, this movie fizzled out. Potential wasted.