Dr. Fate said:
Looking back on the documentaries of the Batman anthology, Tim Burton keeps mentioning that he felt he had to cast Michael Keaton in part because Keaton wasn't an "obvious choice", not tall, muscular, semi-muscular or even stocky, not dashingly handsome, not square jawed... Tim kept going on and on about how those big muscle types don't need the theatrical effect of looking like a giant bat in order to frighten enemies, something someone of Keaton's size apparently needs. So now I try to imagine what it might have been like, Burton working with Kilmer, a more "obvious" choice...
TIM BURTON: "Okay Val, you're looking too tall in this scene, I want you to slouch and shrug your shoulders so you don't look as imposing."
VAL KILMER: "Tim, I can't help how God built me. Besides, shouldn't Batman be im-"
BURTON: "Shut up, it's my film, it's my vision. Also, we need to do something about that jaw of yours, it's too square."
KILMER: "It's the jaw that God gave me, Tim."
BURTON: "Shut up. Also, you're looking too handsome out of costume, so we're gonna have to do something with the hairstylists and the make up people to make you less attractive."
KILMER: "But Tim, with all due respect and modesty, shouldn't Bruce Wayne be-"
BURTON: "Shut up."
Then we get Burton in interviews about working with Val Kilmer...
TIM BURTON: "I never liked the decision to cast Val Kilmer as Batman. To me, Val never really inhabited the character. I always felt that Val was too obvious. He's tall, he's muscular, he's got matinee idol good looks, I just never felt that he needed to wear a bat-suit to frighten people. A guy like Val Kilmer doesn't need the theatrical effect of looking like a giant bat in order to frighten people. It really threw off my vision and-" [suddenly, the hands of Val Kilmer appear and grab Tim from behind, dragging him away, and we hear Tim screaming as he is dragged away]