Now, lets ignore Spider-Man 3 and the Amazing Spider-Man and get this into the open: I loved Spider-Man 3 and I thought it was amazing, but it could have been better. I fucking hate the Amazing Spider-Man.
Now, if I was in charge of the Spider-Man series I wouldn't change Spider-Man and Spider-Man 2, but I would change number 3.
My Spider-Man 3:
How? Storywise, take out the New Goblin and Venom, keep Sandman. My story for Spider-Man 3 would be, Peter is preparing to propose to MJ, Harry decides to try and let Peter prove himself and the two decide to meet somewhere but their meeting is interrupted by Sandman thus shattering the best friends relationship. Trying to catch Sandman, Peter's relationship with MJ also shatters. Peter's life goes from bad to worse when a new photographer, Eddie Brock, gets the staff job that he deserved.
Peter then goes out with his lab partner Gwen Stacy, unknowingly picking up the Venom Symbiote on the way. He is called by Aunt May to accompany her to the police station where he discovers Sandman to be Flint Marko, the man who actually killed his uncle. Enraged, the symbiote takes over Peter giving him the black suit. The black suit makes Peter even more enraged, he ruins Eddie's life, viciously beats Harry (doesn't disfigure him) and ruins MJ's job.
Realizing what he did wrong, Peter seeks redemption, though his ultraviolent acts as black suit Spider-Man have declared him an outlaw. When Sandman attacks a bank, Peter attacks him and starts to lose, but eventually gets the upper hand against Sandman where he confronts him about Uncle Ben. When he learns the truth (the same thing that happened in SM3), he regrets his decisions and actions against his friends and decides to go on a vacation for a while.
So that was my Spider-Man 3, my Spider-Man 4 would obviously have to be different, wouldn't it?
My Spider-Man 4:
Peter, despite quitting as Spider-Man, discovers that he is subliminally continuing to act as him and his methods are getting near suicidal. Continuing his relationship with Gwen Stacy, Peter begins a new life with her, and though Aunt May is sad at what happened with MJ, he is able to handle Peter's decisions. Harry Osborn keeps on brooding and is visited by images of his father who wants harry to take vengeance.
As Peter begins to have a breakdown due to the stress the black suit puts on him, Harry begins to start taking the formula that his father took to become the Green Goblin. Taking off the black suit in the Church, it ends up going to Eddie Brock who decides to use it to take vengeance on Peter for ruining his life.
As Peter's grip on reality continues to break due to what the black suit did to him, Eddie ruins Spider-Man's image even more, branding hm a murderer and all. Eventually, the two decide to meet up with each other where they will have a fight. They do and Peter wins, then deciding that NYC does not need Spider-Man as he will continually put them in trouble.
Post-Credits Scene: Harry puts on the Green Goblin Mask, the silver one as to differentiate himself.
My Spider-Man 5:
Basically Peter is wondering how the city is getting on along without him, but some unprecedented disaster happens and he has to stop it, I'm going for the Vulture or the Lizard on this one.
My Spider-Man 6:
As to end the series, Spider-Man vs the New Goblin.