Here goes some critics about Spiderman III, its just my opinion thou.
Story was the weakest among the three films, I’d say the first film had the strongest storyline and the most clear to follow, but the third film has too much material and very little time devoted to each as if barely scratching the surface, never letting the audience really get involved emotionaly with anything. For example, the story with the sandman and his daughter and wife, so little screen time is given to them while it could have been a great subject to go deep with.
On direction, while I may not be quilified to criticise, as a mere member of the audience, I found some of the action sequences too crowded, the cutting and continuity was sometimes too hard to follow, specialy on the fight with harry and pete in the alleys, it was like they tried to pack in too much goodies into that sequence that it spoiled it all.
On animation, there was some minor stuff, one during the sandman born scene while hes getting up and falling, i think it would have needed more polish, it felt to me that it was somehow rushed in animation. also some of the shots with spidy just screamed computer animation, as they were too clean and perfect to fit into the live action set. As it is with CG animation in live action films, sometimes you need to add those little imperfections, like a few unclean arcs or maybe mess up those slow in/out a bit to make it more life like.
animation of the sandman in the final battle could have been better, I would have personaly added more weight and force to his punch. it was there but could have been pushed more to add more impact.
Overall, I enjoyed the film but the first spiderman remains my favorite.