For Venom to appear, Eddie Brock needs to be in at least one of more of the previous films. There needs to be a series of catastrophic personal events show for which Eddie can blame Spider-man. Without an extended history, we'll have a rehash of Raimi's pathetic Blowpher Venom, even if the new actor actually looks like a man instead of a teenager. In other words, Eddie needs a few years in the timeline to descend to the level insanity that is necessary.
"Yes, and Hawkeye is in the Avengers, but no one ever says, 'Help, Hawkeye.' "--Sheldon Cooper