It's veteran character actor, recent Muppet foe and frequent star of John Sayles movies Chris Cooper. As a thespian, he can pretty much do no wrong, but it's a far less obvious choice than Willem Dafoe was, and certainly skewing older than the darkened 3-D hologram of his head vaguely revealed in the first one.
Is Marc Webb trying to overcompensate for the lack of costume stuff in the first one? Already we have Electro and Rhino, along with some gleefully irresponsible speculation that Harry Osborn will become Venom. Now we have Norman, who will invariably become Green Goblin in a potential part 3 if not this one.
One thing we can say - like Sam Raimi casting Alfred Molina as Doc Ock, Webb appears to be casting good actors regardless of whether or not they look like the traditional incarnation of the character.
Then again, we used to think Halle Berry was a good actress before Catwoman.