What would be your origin/version of the symbiote and what role would Harry Osborn play? And how would Peter meet Mary Jane and what role would she play?
Well, to be clear, in this film, I imagined the film beginning with Peter already donning a black Spiderman suit , minus the symbiote, which reflects his darkened and aggressive attitude.
As he alluded to in NWH, he stops pulling punches and lets his grief get the better of him.
Unfortunately, I couldn't find a manip without the symbiote reflected in the suit.
But, there isn't a symbiote in this story.
The ideas for story I actually came up with in 2014 post ASM 2 ,and pre the Marvel Sony deal.
The jist of the story is, Peter learning to
live again, and learning that past pain, doesn't prevent future happiness.
Kraven, in the story, represents an older version of what Peter
could become. A window into a darker the future.
His life has become all about the hunt and the kill. He's ceased finding joy in life ,and only gets a temporary satisfaction, and a high ,from stalking and punishing his prey, which in this version ,are humans .
Harry Represents the past pain, resentment, and mistakes, he can't get past, and which is like an anchor preventing him from moving forward.
MJ , represents the possibilities of a hopeful, brighter , future.
In this version, she isn't a childhood neighbor, or a girl set up on a date via Aunt May.
She has no connection to Peter's past, and she represents a clean slate .
The story I have in my head is that the film takes place a few years after ASM 2 and he's a senior.
Peter Parker has basically isolated himself from his fellow classmates at Empire State University , and is truly a loner.
He basically fears getting close to anyone for fear that they will end up like Gwen, George Stacy, and Ben.
He's basically become Spiderman full time, and has ceased living due to his mourning and guilt over Gwen.
MJ is a the social butterfly on campus ,who parties through College as a means of burying her own pain.
She's flunking a course that would give her the last credit she needs to graduate ,and she goes to Peter, the social outcast, for help in tutoring for the rest of the semester.
Peter , reluctantly agrees , and I imagine that their dynamic has a bit of friction to it in the beginning.
He kinda lets his smart alec / brooding side out a bit with her, and she can dish it out with him just as easily , and she can do it with a smile.
They both begin to become intrigued with each other ,with both of them realizing there's more to the other than meets the eye.
So , their relationship would go from being testy to becoming friends, though there's a developing attraction between the two of them which Peter doesn't expect.
Peter is scared of the possibility of connecting with MJ beyond just becoming a friend, yet at the same time, her presence in his life is pulling him in a positive direction
As Peter begins to form a new , healthy dynamic with someone, he would find out that Harry Osborn is being released from Ravencroft after 4 years of " rehabilitation" and good behavior.
This sends Peter into a tale spin, and causes him to feel like he's somehow betrayed Gwen by connecting with MJ, and the release of Harry is reminding him that he can't be "happy".
That's about as far as I got in terms of story specifics .

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The rest is a rough idea of how I saw the story playing out
I know Harry ends up dead by the end of the story at Kraven's hands while wearing a black Spiderman suit in order to frame Spiderman.
Kraven would begin to become obsessed with Spiderman , with feelings of inferiority .
He would begin to feel that killing Spiderman would be his greatest conquest, and would give him a warped sense of "peace".
And by the end of it , the classic Kraven's last Hunt scene would playout with Peter being buried alive ala the comics ,and after finding the will to live again, he would dig himself out of the muddy grave in a thunder storm.
After all is said and done, and Kraven is defeated, Peter would put away his black costume, and embrace the possibilities with a new lease on life, and taking a chance with MJ.