Alright, I will try to make my best post to date with arguments I think are worth mentionning.
You need to think of yourself as a writer. We have given information, and we need to take care of everything.
Here is everything we know so far:
1. Electro is a vilain
2. Rhino is a vilain
3. Harry is a friend that turns out to be a Goblin
4. Peter and Gwen seem to be together
5. There's a graduating scene
6. Felicity Jones' character
7. We will learn things about Peter's past
8. Norman Osborn has something to do
9. Gwen Stacy MIGHT die
10. Oscorp are jerks
Now, let's take all those thing and see if they add up. You have THREE HOURS MAX to make it work.
You skip the origin of the hero because it's a sequel.
For the story to work, it needs to contains the following things (no particular order):
1. Introduction
2. You need to develop the Peter-Gwen relationship
3. You need to introduce Harry Osborn
4. You need to introduce Maxwell
5. You need to introduce Rhino
6. You need to *create* Electro
7. You need to *create* The Goblin
8. Harry must have a REASON to dislike Peter/kidnap Gwen
9. Electro needs a REASON to dislike Spider-Man
10. You need cool action scenes so people don't die of boredom
11. You need to find out some things about Peter's past
12. You need to figure out about the whole spying thing
13. You need to give Aunt May some screentime
14. You need to learn what Norman's role/motives is/are about
15. You need to add that graduating scene
16. Uncle Ben/George Stacy must have at least one scene
17. You need to develop a relationship between Peter and Harry
18. You need one (or a few) surprise/twist
19. You need to know what are Oscorp's motives
20. You need a final battle
21. You need a conclusion
That's ALOT of things that needs to happen. If any of these things is missed, the movie CANNOT work. This is a screenwriter law: You DON'T add things for the sake of adding things. Everything MUST make sense.
All I'm saying is with so much things that need to be seen, I fear 3 hours might be not even enough. I have written scripts and I can tell you one thing: pages add up very fast.
My guess is Harry will be introduced in the first 20 minutes. We will see Rhino within the first 30 minutes and Electro will be born under 1 hour. With so many characters, it will take easily an hour to create the whole setting.
So, if BY CHANCE (it's not happening) your runtime is 3 hours, you have a mere 2 hours to resolve everything else. I think 2 hours and a half will be the actual runtime. So 1 hour and a half, or 2 hours at best to to elaborate everything else I mentionned.
THAT'S A LOT OF **** GOING ON!
My point is: You don't have enough time to elaborate Gwen's death in an effective way. If it does happen, it won't be as good as you think it would. There is just so many things that need to be handled in that movie. Adding the death of a major character is a big thing. It cannot be rushed between actions sequences, it cannot happen too fast, you have to be really careful if you want it to be memorable.
Spider-Man 3 was also very over filled with characters and subplots, and it was horrible. But Harry's death also felt unnecessary. It didn't have any impact, it just felt rushed and boring. I always felt that he died so Venom could be considered an ''arch-enemy''.
So yeah. Just think about it. Add everything I have listed above, create a movie about it. EFFECTIVELY, do not come with any far-fetched ********, unanswered questions or ''ass pull'' (look it up, it's a trope)
I want EVERY single point mentionned to be taken care of.
Fail to do this, you CANNOT kill Gwen Stacy. It doesn't work like that, it's unprofessional.
I think there are waaaaay too many things to elaborate in that movie to kill a major character inbetween. It doesn't sound right to me.
Ok, you know me, I'm up for the challenge in order to defend my belief that Gwen WILL DIE!
But before that, let me say OMG. I posted last night and when I came back this morning there's like 7 new pages of posts. Geesh!!!
ALright, here we go:
1. Introduction
Well that's vague. There are so many ways to go for an introduction and many include some of the other things you have listed below. The movie could start with the Aleskei armored car chase scene or it could start with graduation. If what you mean by introduction is a start to the movie then that one os obvious and I'll move on.
2. You need to develop the Peter-Gwen relationship
Well, there's going to be at least two dates (Chinatown and Bazaar). There will be plenty of dialogue there to develop their relationship. Further we know there will be the scene where Gwen does the whol "I love Peter Parker more" and Peter does the whole "This is my choice". I'm guessing there will be some discussion about going, or not going to Oxford, and at least some discussion about Peter and college, about Captain Stacy's death, etc. Most of this will likelt be wrapped together ("I'm not going to Oxford because mom and my brothers need me here." - king of thing).
3. You need to introduce Harry Osborn
We've seen this in the trailer. Peter is visited or runs into Harry and you get the whole "Harry Osborn" - "Peter Parker" dialogue. The introduction will take all of one minute.
4. You need to introduce Maxwell
We know that this will happen during the armored car chase scene. Spidey will save Max from being runover. That's when they have that whole "Spiderman knows my name - it's on your badge" dialogue. Maybe 2 or 3 minutes at most.
5. You need to introduce Rhino
They do not need to get into a backstory. He's a thug who will likely have a Russian accent. That's all that's needed for an introduction and this will be wrapped into the armored car chase scene.
6. You need to *create* Electro
Yes, they will show Max, after we meet him, doing something work related and the accident. I actually believe that there will be two scenes with him getting powers. Effectively watered down initial Electro and then (thanks to Harry) fully charged badarse Electro with the suit and everything. This will take (between the two scenes) like 15 minutes.
7. You need to *create* The Goblin
Yes, we know that Harry will be sent down to the Chamber of the Future, probably by his daddy. Then a mysterious dude (who is not Mysterio), who likes to wear a fedora, will come down, open the doors and show him "the future". The Goblin stuff will likely be in one of the chambers and after Harry loses control of Elecrro he'll take the serum. This is probably around 10 minutes.
8. Harry must have a REASON to dislike Peter/kidnap Gwen
That's like saying Norman has to have a reason to respond to Harry that "not everyone has a happy ending". The fact that Harry will say "We can change the future" shows that he's valuing the possibilities. Plus I xpect that this time, after the transformation, Harry will no longer be himself.
Also we have this pic, which is likely at Harry's place, which will likely lead to what you're looking for, a reason for Harry to go after Spidey.
9. Electro needs a REASON to dislike Spider-Man
Well, he "feels it in the walls". He "feels it in his veins". The point is that he's power hungry and no one will stand in his way. Afterall, "soon, everyone will learn what it means to live in a world without power, without mercy, without Spiderman".
10. You need cool action scenes so people don't die of boredom
The Aleskei armored car chase scene, the Rhino mech scene and the Electro Times Square scens got this covered in spades!
11. You need to find out some things about Peter's past
I expect around 10-15 minutes will be devoted to this. It's what will convince Peter that Oscorp needs to go down, which will lead to Harry being against Spiderman/Peter. We'll have the scene where Harry show Peter that he was under surveillance, Peter confronting Aunt May and then Peter finding his pop's underground railroad lab. Think this is covered.
12. You need to figure out about the whole spying thing
Your 12 and 11 will be wrapped up in the same scenes.
13. You need to give Aunt May some screentime
She'll be at graduation, and as just discussed she'll be part of the discovery scenes where she gets to do the whole "the truth has a cost" dialogue.
14. You need to learn what Norman's role/motives is/are about
There is that whole scene where Harry talks with Norman on his "death bed". The whole "not everyone gets a happy ending" dialigue. This will also be wrapped in with the "I've discovered what Oscorp was using my research for" video that Peter will see in Richard's hidden lab.
15. You need to add that graduating scene
Yup, 5 minutes. I believe it will be the first scene, and it may end up being a nightmare as I've surmised.
16. Uncle Ben/George Stacy must have at least one scene
We know Captain Stacy will be in the graduation scene. The only question is whether Peter will go to his grave for another 5 minute scene. Or will that be Uncle Ben's grave instead. Do we have confirmation that Ben is in this one?
17. You need to develop a relationship between Peter and Harry
We know that once Harry comes back Peter and he will spend a scene reaquanting, and then the whole "Oscorp had you under surveillance" scene. The reaquantence scene may be another 5-10 minutes.
18. You need one (or a few) surprise/twist
Obviously you are implying that the twist will be Gwen not dying. But Harry turning into the Goblin is a twist, just one that we've figured out. Also Gwen dying at the clock tower, and not the bridge, would have been a twist since they will be at the bridge (and I suspect that Peter will save her there - in a different way - prior to the clock tower). Also, who the fedora guy is might be a twist (imagine if it's Richard Parker?????).
19. You need to know what are Oscorp's motives
Already covered under #14 above since Oscorp's motives are Norman's motives.
20. You need a final battle
I'm pretty sure we saw this little action bit between Electro and Spiderman, as well as this little clock tower scene. I think those consequtively will cover it!!!
21. You need a conclusion
Like Electro being defeated and then Goblin getting away due to the death of an important character? Boy people are going to cry! What a way to end a movie!!!
I would agree that if they had Gwen's death in the middle of the movie they would need to spend a lot of time on the aftermath, but that's not what I think will happen. If they kill her as part of the huge finale, it makes more sense. It leaves the movie as an OMG! People will walk out of there with tears in their eyes saying "I can't believe they killed her". Not us, we'll be like "Yup, saw that coming", but the GA will be taken aback, which is what the writers want. But the point is that they wouldn't need to spend 15 minutes on what happened after. Will they show us Gwen's funeral? Maybe, but possibly not. It all depends on how they end it and it could be left to be dealt with in TASM3. As a writer I'm sure you will not like that way of handling things, but it's possible.