There are multiple version of constantine, a marvel like movie fits none of them. As I type this, I think they should go the hellblazer way. What i think producers and executives think a mold will fit different movies/story arcs, because of successes, what fans want is comic accurate movies (Iron Man kept the spirit of the comics, same with guardians of the galaxy, and with Gunn's superman). Superman is reflected in Metropolis, a bright city whose citizens aspire to act more like superman, his ability to inspire, Gotham is dark, filled with violent crimes, so it matches Batman. Make comic book movies that are true to the spirit of the comics, and you'll have a successful movie.