As I looked today at the image of Harry Osborn from the leaked ASM2 poster, I seemed to realize something: He doesn't really look like the Goblin we all know and love, right?
Well, I thought of something: Norman Osborn will be "sick" the entire movie (possibly) right? and Harry is apparently the Goblin?
Here's my theory:
In the end of ASM2, (I'm assuming Electro is placed in prison along with Rhino before this scene) The (possibly dying because he's been wounded in battle) Goblin Harry will go to his father and inject him with the serum he took, making his father "better". Norman begins to become healthy, but instead it takes a wrong turn and he's transformed into the Green Goblin. This is the green goblin who looks like how he did in the comics, only the face is not a mask, Norman is forever a mutant with green skin and pointed ears (basically the costume from the comics is his actual body, only much more frightening.)
Norman will kill his son (due to being insane from the serum) and steal the glider and suit, along with some sort of mask or headgear.
This leads to one thing: The climax.
In the climax, Norman goes and finds Gwen Stacy and ends up killing her to taunt and piss off Peter Parker.
Peter and Norman duel in the sky and through the streets of New York City
Peter and Norman trade blows and pumpkin bombs until Norman is wounded just enough (possibly by his own glider) to retreat, leaving Peter with Gwen's dead body.
He mourns and is forced to deal with the fact that he "let her die" and has broken his vow to Captain Stacy to keep her safe.
In the final scene of the movie/mid credits scene, Norman will break into the prison and free Electro and Rhino, all of them vowing to destroy Spider Man together...thus making the beginning of the Sinister Six.
Tell me what you guys think.