Consider what it would've been like if there was an Internet back in the 1980s when Warner was developing the first Batman movie, when some folks started out wanting to cast Bill Murray as Batman, in a campy version of the character leaning more toward the 1960s TV series than the darker, more adult version of modern films. Imagine how today's Internet fandom and fan sites would've reacted to new of the first negotiations with Michael Keaton, or to the early talks and decisions to hire Pee Wee's Big Adventure director Tim Burton to direct a Batman movie. We'd have heard that the script kept being rewritten and changed, that one director on the project wanted Eddie Murphy to play Robin, that there was no real ending while principal photography was taking place, and we'd have heard leaks that they changed Batman's origin so the Joker killed Bruce Wayne's parents. We'd have seen leaked set photos of two musical dance numbers with Prince songs. The fan meltdowns to this steady march of information leaking out constantly from the earliest stages of development would've been of epic proportions.
Seriously take the time to think about how fans of today would react to all of that -- it would've been an explosion of fan outrage, fear, and depression online.