Whenever people stop watching movies in the future, someone will look back on the list of actors who were almost cast in comic book movies and it will be indistinguishable from a general list of the best talents of the Hollywood era. Such is the rise of the genre that pretty much everyone working - be they classically trained thespians, Oscar-regulars or action movie royalty - will find themselves linked to a character who started out on the pages of DC, Marvel or one of the lesser brands.
There are those who've turned the opportunities down flatly (sometimes because of prejudice against the material), those who've simply not been able to take on the work and those who wanted to be cast but didn't make the cut. That last category must be particularly galling - particularly when the role you go for seems so perfect for you.
Even within the hierarchy of comic book movie roles, there's a special status afforded to members of Batman's Rogues Gallery: those nefarious figures are so well-known that the opportunity to play them must be irresistible. Or so you'd think. But for every actor who failed the audition (sometimes on purpose), there are also those who just plain didn't want to go toe-to-toe with the Dark Knight. And either way, that means we were robbed of some truly memorable potential performances.
Had these alternatives actually happened, it might not have led to bad results, to be honest...