More than likely we will see Venom in one of the Amazing Spider-man films. One way or another. And chances are it will be Eddie brock. Well here is my idea for how to make a Venom movie afterwards.
After venom is defeated in The Amazing Spider-man 3 or 4 which ever. The government gets a hold of the symbiote and works on a program. We see Flash Thompson join the Marines. Two of his friends in his group are Frank Castle and Cletus Kasady. The three of them on a mission get stuck in a firefight against impossible odds. However they somehow hold out until back up gets there, by the end of the fight however Flash has lost his legs, and the other two are mentally unstable. Flash was asked to join a secret program involving super soldiers, of which he excepts. Meanwhile Frank and Cletus escape their New York hospitals and both go separate paths. Flash joins the venom program and gains a suit to begin his special missions. Frank begins to do what he does best, killing bad guys. We see Frank turn himself into the Punisher and start, meanwhile Kasady has gone insane and begins serial killing. Flash on his second mission loses control of the suit and is returned to New York where he again loses control and runs off with the suit. He begins to chase down crime and attacks Kasady, Frank who was already tracking Kasady opens fire on Flash. Going full blast the Punisher blows part of the suit off of him. The Symbiote now unstable and back to its original form clings to Kasady as he runs away from the scene. Venom defeats frank but recognizes him and spares his life. He asks for a team up but the Punisher leaves. Flash goes to his old friend peter for some help and tells him his secrets. Peter reveals that he is Spider-man and the two of them set out to stop the Punisher. Before they reach him they are attacked by Kasady now Carnage and they fight. Carnage kills Venom during the fight but is eventually stopped by Peter and Frank as he comes to help. Frank leaves telling spider-man he never wants to see him again. This sets up the Punisher’s own TV show and possibly another Spider-man film.