id rather have a clever cgi Venom, but if they did have a prosthetic suit they could cover it with slime to look shiny lol. Topher might be too small and Venom would be roughly the same height, maybe an inch taller but with a wide load...it would be awkward. They'd have to edit each scene to take out wrinkles that show up - like in Hellboy, but F4 they did not bother with it.
I think the best option would be not to even have Topher don any type of suit for Venom, basically have him just play Brock.
Have someone else as the Venom body - a guy who's taller and way more muscular than Topher is. Combine that with CG additions, such as the tendrils flaring, the slime, the tongue and whatnot.
As for voice, either heavily manipulate Topher's to make it really, really different (deeper, slightly raspier, more evil sounding since Topher has a really calm and simple voice), or just get a voice actor to do the work. Get someone who's done voices for characters like that, hell even get the guy who did Venom's voice for the animated series, but spruce him up a bit. That'd work even.
What about if Venom went complete CGI like for Hulk?
I think hulk was plausable enough to look real so theres no reaso it can't work with venom, He doesnt even really have a face. But maybe even that would spill their budget a tad..
Well venom does roll his symbiote face back to reveal Eddies face every now and then, so how would they do that if there was a scene where he did that?
Put Topher on a Green Screen stage and film him doing that. Tke of his head in computer and place it under Venoms face and roll Venoms face back to reveal- *shock* Eddie
Well, I can agree with some of that, but we haven't seen if he can do some sort of deeper voice, but a voice actor would be cool. They should do the double-layer that they did in the animated series. If they got a body double, the best bet would be the guy from Resident Evil: Apocalypse, because he's the right proportions (he actually looks like Brock too!) Also, if they got a good animatronic mask like the ones used in AVP, then they could do a great job. However, I bet they'll go with the CG.
True, we haven't heard him do a Venom voice yet. I'm sort of judging him by what I've seen already, but he might be able to do an awesome voice.
And yeah, I think they'll go heavily on CGI for Venom. If they use Hulk as a springboard, but of course, not make it weird like Hulk did, they can pull it off. If they fix the Hulk flaws they'd have a good Venom. At the very least, the expressions on Hulk's face were pretty good.