It was what Venom's creator had always planned: Brock gets killed and the symbiote would go around bonding to other people and some of Spidey's other villains to continue menacing Spidey.
I just think if they made Harry into Venom then it would make him more separate from his father as a villain so he wouldn't always have the "He's not as good as Norman" comparison, and they could even co-exist as villains.
