Kraven the Hunter

Desperate to be known as the world's greatest hunter, Sergei Kravinoff, or Kraven the Hunter, has been hunting Spider-Man for a very long time.  Kraven first appeared in 1964, and was created by Stan Lee and Steve Ditko, and has long been a favorite of Spider-Man fans.  Kraven is a big game hunter, imbued with enhanced physical abilities through a series of magical potions, that relishes hunting more than anything, going so far as to use his hands over guns.

So what would we see if Kraven was brought to the big screen?  Well, a movie with such a simple villain, basically just a hunter, could spend a lot more time with big action sequences rather than boring character development.  The last Spider-Man suffered from far too much time trying to manage all its villains, and their respective back-stories, so this might be a way to forgo the same mistakes made in Spider-Man 3.  But would a simple back story make for a pointless character?  I would be slightly concerned at one of two things happening here, one, Raimi and company creating a character that no one understands or cares about, or two, Raimi and company weaving a ridiculous and over-the-top back story for Kraven.

Casting Possibilities:  Jeffrey Dean Morgan, Javier Bardem, Benicio Del Toro, Andrew Divoff (Mikhail from LOST), Ian McShane, or Jean Reno.

Lizard

Lizard has also been in the Spider-Man zeitgeist for a very long time, first introduced in 1963, and also created by Stan Lee and Steve Ditko.  Dr. Curt Connors, played in Spider-Man 2 & 3 by Dylan Baker, seems like the most likely villain in a fourth film.  His relationship with Peter Parker has been developed over the last 2 films, and he has solidified his role as mentor.  Well, he could become a mentor if they spent some time developing the character, anyway.

In the film series Dr. Connors is a physicist, rather than a biologist, so there are some continuity differences, but a Spider-Man movie with Lizard is better than a good idea, it just makes sense.  In comic book movies, more villains, equals crappier movie.  It’s not a rule, but it’s definitely a leading indicator.  When there are villains spread out, i.e. Spider-Man 3, a lot gets muddled, too much time is spent trying to establish too many motivations and characters.  Dr. Connors is known to the audience, he's already lost his arm, so his transformation could easily be set-up, and he would add continuity to the series.

Mysterio

There has already been speculation that Bruce Campbell might be stepping into the role as Mysterio, but that is only a rumor.  There have been rumors in the past, before Spider-Man 3 was released, that we might be seeing Bruce Campbell as Mysterio, which, or course, didn't quite work out.

Mysterio is a special effects expert who, believing he has conquered the world of film, decides to frame Spider-Man, apprehend him, and himself, become New York's greatest superhero.  Things didn't go to plan, and we have Mysterio going into the far more lucrative business of being a super-villain.

Honestly, I think the only way this character can actually work is semi-humorously, unless they change Mysterio’s back-story quite a bit.  The motivations behind the character are just not quite solid enough for Raimi's Spider-Man world, so why not go a little overboard, and make Mysterio incredibly arrogant, a complete egotistical load-mouth.  Doesn’t that sound like a character Bruce Campbell could play?

Casting Possibilities:  Bruce Campbell, Patrick Warburton, Seth Rogen, Matthew Perry, Robert Downey Jr., or George Clooney.

Scorpion

Another villain who's been around since the 60's, Scorpion has a long and varied history in the Spider-Man world.  Not only has Mac Gargan been Scorpion, but he’s also been Venom and he even impersonated Spider-Man for a time. 

Scorpion’s costume is the biggest point of contention for me.  How do you render a realistic character that’s in a green scorpion costume?  Now, the Scorpion suit is a metal battle suit, so they could go with a really badass, Iron Man-ish style suit.  They could even forgo an extended scene where he creates the suit, and pull a Doc Ock, and just have the suit creation happen off screen.  Most of Spider-Man’s other foes are supernatural or superhuman in some way, so a character who’s power comes entirely from a power suit might be an interesting direction.

Casting Possibilities:  Brad Dourif, Clifford Collins Jr., Steve Buscemi, or Crispin Glover.

Carnage

One of the newer villains, and a serial killer in his pre-super-villain life, Carnage could give us the movie that many of us wished Spider-Man 3 was.  Venom just didn’t live up to the expectations of many, and Carnage was created to be a darker, more violent version of Venom.  And his real name is Cletus.  Isn’t it about time that we had a super-villain named Cletus.

One of the many things most disappointing things about Venom in Spider-Man 3 was that he simply didn't look like Venom.  Sure, the black suit was there, the huge fanged mouth was there sometimes too, but Raimi used Topher Grace’s face rather than Venom’s through most of the movie.  But I digress, Carnage is similar in many ways to Venom, so using Carnage as a villain would give the filmmakers a chance to make things right.  Unlike most Spider-Man villains, Carnage is truly terrifying and would give the filmmakers a unique opportunity.  Eddie Brock was just a confused kid who fused with Venom, Sandman was a complicated character with a cute daughter, and Harry Osbourne ended up being a good guy in the end, but Carnage would be entirely different.  In Carnage we would have pure, unadulterated evil, with superpowers.  This seems like a perfect way to up-the-ante in the Spider-Man series, and sort of reboot the tone of the Spider-Man 4, without having to make radical changes.

Casting Possibilities: Ryan Reynolds, Timothy Olyphant, Matt Dillon, or Jake Busey.