I thought of the S6 as well, could be a way to bring in the symbiote as well. Harry brings the six together to take out Spidey. Spider-Man gets torn apart, he just barely gets away, the costum is completely shredded. The symbiote comes into play from JJJ's son bringing it back from some space mission, Peter comes in contact with it and it joins with him. Spidey then has to run the gauntlet of the six<I know they did this in one of the comics where he had to fight each of the six one by one> with Harry being last, with the symbiote he tears through the first five like nothing. mid-way through the fight with Harry he realizes the symbiote is taking controll, he's now trying to fight it of along with Harry<this would be the time in the fight where the villain gets the big upper had before the hero makes the big come back.> Spider-Man avoids the "death blow" from Harry and dumps te symbiote, he finishes the fight as himself, good conquers evil, blah, blah, blah. The movie ends with Eddie Brock coming across the symbiote<early in the movie we'd have to introduce Brock and establish the relationship with him and Parker>
But that's probably way to much then they could fit into one movie unless there were very few non-action scenes as you'd have the first fiht with the si where Parker gets torn apart, and the six seperate fights<though Spidey wuld finish the first five off rather quickly establishing the power of the symbiote>