About Venom, I'd rather they take their time with that. I want to see a whole movie with Spiderman in the Venom suit, then at the end he rips it off and in a later film Venom forms and goes after Spiderman. I'd also skip straight past Eddie Brock and on to Flash Thompson. My trajectory for Flash/Venom goes as follows:
> Spiderman 2017 - Flash is Peter's high school bully. But he's a big Spidey fan.
> Spiderman 2 - Flash gets a security job at Oscorp and proves to be very talented. But loses his legs in an accident.
> Spiderman 3 - Peter finds the symbiote suit. At the end he tears it off and it makes its way to Oscorp to team up with Osborn and get revenge against Spidey. Osborn chooses Flash as the test subject for the symbiote bonding.
> Thunderbolts Movie - This movie would focus on various villains from Phase 3 teaming up, including Venom and Green Goblin.
> Spiderman 4 - Venom as the main villain. Eventually Flash takes control of the symbiote.
> Agent Venom franchise, Guardians crossovers etc.
ETA: They could sort of take Eddie's hatred for Peter/Spiderman and transfer that to Flash. Maybe Flash blames Spiderman for his accident and wants vengeance. But eventually he realises that Venom has taken him too far, and he manages to wrest back control and become Agent Venom.