Given the time it takes to make a feature film, it isn't surprising that things change dramatically across the span of the production process. A movie can look one way in the beginning, only for it to end up as a completely different beast by the time it actually ships into theatres.
One reason for this comes down to casting, of course, as famous actors sign to play certain parts, only to exit and wind up being replaced for an incalculable number of reasons - scheduling conflicts, creative differences... you name it, it happens.
Sometimes actors um and ah over certain roles, too, generating huge levels of excitement from fans when their names are linked to the film in question, only for said actor to turn down the part unexpectedly and go elsewhere, transforming the movie in the process as it's shaped around the next viable actor on the list.
2017's biggest and most notable movies are no different, most of which started their journeys into the theatre with other actors either being considered or outright vying for the most important roles.
How would the cinematic year have shaped up had they agreed or been cast instead, then?