Well, it makes it more alike new own idea of a Spider-Man trilogy titled The Goblin Saga
1st movie
> villain: Green Goblin
Ends with Norman's amnesia; forgetting his Goblin persona, that Peter is Spider-Man and the threats he made (killing everyone Peter loved, including Aunt May and Gwen)
2nd movie
> Dr. Octupus
Norman, without his evil side becomes a nice man and good father to Harry which makes Peter struggle with being Spider-Man, because it's continuation might make Norman remember.
3rd movie
> Green Goblin and The Spider-Slayers
Norman remembers, but plays it differently. Instead of going all physical, Norman plays is more mastermind like. We see his more cunning side. He finances Dr. Spencer Smythe into creating the Spider-Slayers (instead of Jameson). In the end, GG kills Gwen and "dies", Smythe also dies by the Norman's hands.
FYI, i have already an idea for the follow up trilogy entitled The Night of the Jackal.
I still say this movie looks extremely mediocre, in fact, lately, all superhero movies do.