Modern Hollywood executives would want Moby Dick to be a zombie whale. "That's why he's white; he's not albino, he's rotting! And that's why he's so powerful and hard to catch; he doesn't know his own strength! And that's why sharks follow it! Food! And if he's a zombie, we can make it more sympathetic, like Bub in Day of the Dead or Big Daddy in Land of the Dead. Because we have to have more Moby Dick in this; the book barely has him..."*
(I also can picture execs asking "Does he have to be a he? Hey, the book just assumes Moby Dick's male!")
Or maybe Hollywood would want the whale to have jet engines on his flukes and machine guns on his flippers. (He would if he appeared in Axe Cop.) Or be a submarine in a whale disguise! That's how Captain Nemo avoided 19th century authorities! And would explain why Moby Dick is so much larger than a sperm whale should be!
...I think maybe reading Moby-Dick has possibly warped my brain. More. I mean warped it more.
* I'm being flippant, but there's a serious attempt to write a version of Moby-Dick where the whale really is a zombie. At least it was still serious as of this blog entry...