They kept struggling to have storyline in which Vulture was connected to Peter Parker AND Spider-man. What they had going at the most was the current theme of revenge and/or forgiveness. The Vulture was put in prison because of Spiderman, so Sandman would help him escape, and the Vulture would make his wings out of objects he found. Sure yeah the revenge part may have been there... Vulture wanting revenge on Spider-man, but that wasn't good enough. It was on March 15th 2005 that they decided to drop vulture and have Venom stay.
So yeah since the theme will obviously be different in the potential fourquel, there may be a chance for Vulture. Although I'm predicting a theme of trust between the town and spider-man and I can only see either Lizard, Mysterio, Kraven, or Black Cat involved.