There is so much wrong with The Amazing Spider-Man 2 that it's hard to find one place to begin criticizing the film. The finished film has a weird quality that makes it feel as though director Marc Webb reconsidered the whole thing halfway through production and made a huge course correction, but an early draft of the script by Roberto Orci and Alex Kurtzman shows that the film's problematical plot elements were always in place. But there were some aspects of the early draft that are very different from the finished film, and I wonder if getting rid of this stuff hurt the movie.
1) Mary Jane. As we all know Shailene Woodley was cast as Mary Jane Watson, shot some days and then was cut from the movie. The original script includes all of the MJ scenes, and she's introduced as the Parker's new next door neighbor. Her dad is an abusive drunk and she's a waitress who builds motorcycles in her spare time. She has a Spider-Man tattoo on her wrist, and she's clearly interested in Peter, who is totally hung up on Gwen. At one point Spider-Man confronts MJ's dad, telling him to lay off the girl. At the end of the script Gwen comes to Peter's house before heading to London; he's gone but she meets the new neighbor. They have a friendly exchange and MJ says that she always attracts dickheads and asks Gwen what her advice is to get a guy like Peter. "Date a nerd," Gwen says before heading off to die, basically giving MJ the okay to get with Peter.
2) Electro's mom. In the script Max Dillon lives at home with his wheelchair-bound mom, who doesn't think much of him. He has to take care of her, and after he 'dies' in the accident that gives him powers he comes home to find his mom standing up and getting a big payout from Oscorp. He gets angry and begins using his powers, which is what sets off his confrontation with the police in Times Square, not a weird moment where he just starts sucking on electrical wires for no reason.
3) J Jonah Jameson. JJJ's in the original script, as is Robbie Robertson. We see Peter, who is a student at Empire State University, bring his first Spider-Man pictures to JJJ, who gives him a tour of the Daily Bugle. JJJ complains that the internet is killing the newspaper business; later, Spidey and Electro's first fight send them crashing through the Daily Bugle offices and the printing presses.
4) Peter's blood. In the original script Peter actually gives his blood to Harry Osborn. This is a huge improvement over the finished film, where Harry just injects himself with spider venom. In the original script the Goblin suit is better explained - it isn't for military use but was specifically built in secret for Norman Osborn. When Richard Parker wouldn't give his blood to Osborn (the Parker DNA still being the key to it all), the suit went into Norman's boathouse where Harry finds it.
5) Dr. Kafka and Electro's escape. In the finished film Dr. Kafka, the scientist torturing Electro at the Ravenscroft Institute, is a man. This is a genderswap, as Dr. Kafka is a woman in the comics - and in the original script. She is absolutely specified as a female character; why Webb chose to change this detail is beyond me. Also, Electro breaks himself out of Ravenscroft, and he approaches Harry Osborn at Norman's grave in an attempt to kill him. When he sees that Harry is now The Goblin the two team up.
6) One year later. In the original script there's an entire year gap between the high school graduation and most of the rest of the film. This year gap makes Peter's forlorn attitude towards Gwen cute instead of creepy, and it establishes that they're college students. This makes Gwen's application to Oxford make more sense - in the finished film it's like she decided to go to college at the last minute.
7) Dr. Ratha. In The Amazing Spider-Man the character of Dr. Ratha seems to have been killed in deleted scenes, but the actual movie leaves him alive at the end. He shows up in the script for The Amazing Spider-Man 2, filling the same role as Donald Mencken, the Colm Feore character. Basically having Ratha appear as the Oscorp stooge who engineers Harry's dismissal from the company lends a nice continuity to the film, which in many ways feels like a reboot of the reboot in the first place. All of the basic elements of Ratha's role are in the finished movie, there's just a different name attached to the character.
8) Little Spider-Man. One of the best sequences in the movie has Spidey helping a nerdy little kid who is getting picked on by bullies. That kid shows up at the end, in a Spider-Man costume, to confront the rampaging Rhino. That kid isn't in this script! And the Rhino barely is either; he's just a cameo at the end, with no connection to the truck heist at the beginning of the film.
9) The death of Gwen Stacy. It plays out mostly the same in the original script... but Gwen, back broken, hangs on to life long enough to demand that Peter never give up. Because this is the same character who promptly broke his promise to Captain Stacy in The Amazing Spider-Man, Peter quits being Spider-Man in the next scene.
10) "With great power..." The finished film has a terrible bit at the end where Peter quits Spider-Man for a bunch of months, and this time passes by in a montage. The same thing happens here! But instead of finding a tape of Gwen's super on-the-nose graduation speech, Peter is approached by... his dad! Yes, Richard Parker shows back up at the end of the script, and he tells Peter he's been watching him for years. He's seen him become Spider-Man and everything. It's Richard who convinces Peter to become Spider-Man again, and in his last scene in the movie he tells Pete "With great power comes great responsibility," FINALLY working the famous phrase into this new series.