First off... Venom won't be even a minor part of this movie is my best guess. If anything he will be in about 5-10 seconds at the end of the movie where we see the transformation and then this clip we see now of him lunging towards the screen before the movie cuts to credits. If we get any more then that I will be impressed.
Secondly... Hollywood doesn't like quadrilogies. Very few movies make it past triology status simply because Hollywood buys into the fact that movies only keep their viewership for so long and won't make money after that. Each movie costs more and more to produce as actors salaries and special FX become more demanding, so even tho a 4th movie might do good at the box office the profit won't be as great. How many movies off the top of your head can you think of that have more then 3 iterations? Even the hugely successful movies like Indiana Jones, Back to the Future and most presently, XMen don't have a 4th movie.
Yes I know a 4th Indiana Jones is in the works but thats like 20 years after the third and kinda counts as a new saga with a whole fresh batch of teenagers/young adults to not be bored with it (same way Star Wars did it). And the only way we will see an Xmen 4 in the near future is under a different name (Wolverine?).
Spiderman 4 could happen... but with the previous background knowledge I just posted and the fact that the actors only signed on for 3 movies (this was known since the 1st Spiderman movie released), it may be a long shot. Maybe the 4th one will be called Venom? Or maybe Ultimate Spiderman or something, I doubt many if of the same actors would be in it though.
