Well, from what we know thus far, Topher said that Venom loves being bad/evil, and I believe Tobey said that Venom is faster, stronger and vicious than Spidey with all of his powers. That pretty much sums up Venom's characterization in a nutshell. And his look, you've seen the leaked trailer by now.
Screentime, you all ready know that that's limited, and the Q & A said Eddie Brock dies. Which doesn't make any sense on a business level to the franchise, because with a dead Eddie Brock, you can never bring back Venom to future films. Unless Sony/Marvel realize by now, that killing Eddie Brock (after all the Venom uprising) could mean never returning the character to the big screen in his own movie, which could be very profitable for another future Spidey film for SM5-SM6.