When the production for Amazing Spider-Man 2 was underway, reports earlier stated the sequel's villain would be Electro, but then as the executive producers felt that Electro alone wasn't enough, they casted Paul Giamatti as the Rhino.
As for Chris Cooper, the producers casted the 61 year old actor as Norman Osborn better known as Spidey's arch nemisis the Green Goblin.
And as for Thor actor Colm Feore, his role was kept secret until now as reports stated that Feore's role has been confirmed as the Vulture. Vulture was also the villain that Sam Raimi was planning to use as the main antagonist in his fourth Spider-Man film until he cancelled it for the reboot to premier at the character's 50th anniversary. Thanks to Feore's confirmation as the character it makes up for the delaying setback. However all that remains a mystery is whether the character will actually be the villain from the Comics or just a normal businessman.
With the slight possibility of the Sinister Six appearing togetherat the number of 4 actual supervillains confirmed, only two remain unconfirmed.
Chances are that it will be both the Lizard and Morbius or some other villain from the comics but to find out stay tuned for more updates on the film as shooting continues.