It was dropped. He stopped looking or caring about the killer and it wasn't referenced again by anyone. Not only is that a disservice to the character of Peter becoming Spider-Man, Peter's entire motivation of trying to find out about his parents and find Ben's killer are completely dropped the second Curt takes the serum.
It isn't actually dropped, the film clearly shows its still on his mind...but the film also shows Peter realizing that he can use his powers to protect the innocent VS seeking vengeance for himself. This is a major plot point. This aspect of his powers becomes more important to him than seeking justice for himself. This is key to the film, and to the franchise, and its resolved in one film. This is integral to Spider-Man's mythology. Spider-Man is not about revenge. Spider-Man is about using his powers to help others.
The entire first act is about Peter's parents and Ben's killer. Then it's dropped.
No...it very much isn't dropped. It evolves with the story. The story about Peter's father's work segueways into the story about Curt Conners, because Curt Conners is continuing Peter's father's work. Peter himself completes his father's work, but then has to find the cure for the formula he helped create. It's like, the focal point of the film, and arguably the film's main story.
Name me another movie that dropped 2 major plot arcs for the main character (the entire reason for the existence of the first act) so that the sequel can have more depth.
"Dropped" is the wrong phrase to use. "Unresolved" is more like it, but only certain elements are unresolved, and that's based on people's assumptions about what may have originally been planned. I think people have already pointed out that X-MEN does something similar, in terms of Wolverine's past. It gives us glimpses, but does not resolve this element, and leaves the details of his past for a sequel. THE MATRIX films did something similar with various storylines and themes. In terms of more obvious examples, the STAR WARS films come to mind, in terms of movies that introduce plot points and themes that are not resolved until later films, both trilogies. The previous SPIDER-MAN films did the same thing, especially with Harry Osborn's arc. SUPERMAN: THE MOVIE and SUPERMAN II had similar elements. Witness the introduction of the Phantom Zone villains in SUPERMAN: THE MOVIE which did not pay off until SUPERMAN II. BATMAN BEGINS has elements of this type of storytelling as well.
I can't come up with a ton of films that have done this, because its not done all that often. But neither did this one just "drop" ideas it introduced. It developed both a self contained story AND introduced overarching themes that the filmmakers planned to use for the entire franchise, which they never intended to resolve all in one film.
Thats not doing something "unique" it's just not something done when writing, because you need to leave the audience with some kind of satisfaction like they actually saw a story being told. You can have a set up film, that is a story within a bigger story, you don't have to do this to set up for the future.
There WAS a story being told. There were several of them.
The story of Peter Parker's transformation into Spider-Man and his acceptance of responsibility.
There's also the story of Peter discovering his father's work, and this leading to his discovery of Connor's ongoing work with his father's ideas, and then Peter's eventual involvement/completion of his father's formula. That storyline was resolved in this movie. That's a self contained storyline, and its all in this one film.
There's also the story of Peter and Gwen becoming a couple, and being tested as a couple.
You really think that TASM has anything resembling a 'unique structure'? It's not pioneering a bold new method of storytelling or taking a risk on an unconventional story structure. It tells a pretty rote origin story but doesn't resolve some sub plots because it wants to set up a sequel. How many films have done that or something very similar in the past 5 years even?
Of all the arguments that could be made to respond to legitimate concerns about dropping plot points, I really don't see how innovative film making is one of them.
I never said innovative. I said unique. Is it entirely new? No. But it is somewhat unique for a film of this genre. Otherwise, people wouldn’t be whining about how “No other movie does this!”
I don't think its about just wanting to set up a sequel. Its about developing themes and concepts that the entire franchise will explore. Its not just a film with sequel bait elements in it.
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