And let's just say if it does good in the box-office, just like AvP, if Venom makes one or two sequels, they could always add additional symbiotes, like have a storyline where the symbiotes invade Earth and perhaps a backstory involving where the symbiote comes from.
Just an idea, lol.
P.S. I heard that, since Eddie Brock, Jr. DIED in Spider-Man 3(he did die people, face the hard, but true, facts), his father Eddie Brock is "supposedly" going to be in it...now, if they go by the Ultimate version(which they did with the Jr.), then the actual Eddie Brock is a scientist/doctor, and what if, a piece of symbiote escapes New York from that final battle in S-M 3 and it wanders off into the woods(close to where it landed in the first place), where Eddie Brock, the scientist, is out there, trying to find some natural ways to cure cancer, and himself(would be a nice twist, to have him have cancer too...and of course, this would be cool if it happened that same night), and it grabs unto the real Brock, who becomes insane during that night, then wakes up to find this symbiote on him, tries to test it to see if it it the needed subject for this cure, and something happens, where it spawns a "child".