2. Robert Pattinson
What more fitting a casting could have been made than the man who has already played the character on which Christian Grey is based? Fifty Shades was infamously first written as a Twilight fan fiction, with Christian Grey and Anastasia actually Edward and Bella, so it would make sense to return to source of sorts to cast Christian. Pattinson was cast as Edward once, and though the films were largely terrible, he actually inhabited the character fairly well. He has everything in his locker that suits Grey - he can play aloufness and darkness and he can convince as a removed hero with the kind of anti-charisma that fans will want to see in the character. Pattinson might well have been a non-starter, since he will now clearly be looking to reinvent himself and not be caught in the reductive vicious cycle of type-casting, and effectively playing a porn version of your most famous character isn't exactly the best way to escape from that character. He would have been a movie marketer's dream, since he has an established fanbase already, and of course, the casting would have been the perfect fan service who came into Fifty Shades having already loved Twilight.