Looks like The Amazing Spider-Man 2 will be following in the Spider-Man 3 tradition of too many villains and the use of Sideways as a rogues gallery.
THR reports Paul Giamatti is in talks to join the film as Rhino, the Spider-Man villain that is a man's face sticking out of a rhinoceros pelt. And there's no reason to think Giamatti won't be taking the role, even if there is already a cartoonish villain in Jamie Foxx's Electro: Back in 2011, the actor made clear his willingness to wear a rhinoceros costume with just his face sticking out, telling ShowbizSpy:
"I thought Rhino was the greatest thing when I was a little kid. It was a guy who was basically in this rhinoceros outfit and I always thought, 'Why don't they have The Rhino in one of their movies,' but maybe The Rhino wasn't that big of a deal for anybody but me.
"If they ever go with The Rhino I would be ready and waiting."
Cemetery Junction's Felicity Jones is also reportedly in talks to join the bloating cast, which includes returning stars Andrew Garfield and Emma Stone, as well as Foxx and fellow newcomers Shailene Woodley and Dane DeHaan, who are playing Mary Jane and Harry Osborne, respectively. Her role isn't being revealed, but judging by Sony and director Marc Webb's eagerness to set-up future relationships and villains--and because her name is close enough already--it wouldn't be surprising to learn she's playing Felicia Hardy, better known as Black Cat or "basically Catwoman, but for Spider-Man, and she has white hair."
Also, in the end credits, Sandra Oh is going to reveal she's Carnage.