I had read in an interview that Sam Raimi does NOT like Venom, and pretty much said that Venom would never be in a Spiderman movie he directed.
I remember hearing the same back when the first Spidey came out. And being elated, as I was never a big fan of Venom myself. But I don't think Raimi can hold out against studio and fan pressure forever. And I wouldn't put it past Raimi to come up with what he considers a creative way to handle the origin and nature of Venom that makes him palatable enough to put him on the big screen.
If I'm not mistaken, Raimi is signed through this one and he's out. Which leaves us with the possibility of three villains in
Spiderman 3, as I seriously doubt he's going to leave the Osbourne angle alone for someone else to finish. Perhaps Topher will be a scapegoat for Harry? Or maybe he'll be Hobgoblin? I'm worried that this film is going to take on far too much for one film and end up diluting all stories involved. Unless one of the villains is a glorified cameo fight at the beginning of the film. Which could be really, really cool.