Really, there's no such thing as a 'comic book movie'. The movies are based off pre-existing stories/characters which, like it or not don't always adapt well to the medium of film. This is the case with adapting anything from another medium into film; TV, books, Broadway, plays, even artwork. It's easy to say a comic story would make a good film, but that's not always the case, in fact it rarely is the case. The directors/writers don't deliberately piss fanboys off by changing characters/story lines, they do it to adapt it well onto screen. They have a job to bring entertainment to movie goer, which like it or not, is a bigger audience they have to cater for than comic book fanboys. To answers the question, no they shouldn't listen to fanboys, and to be honest, it's best they don't.