My view is, if the demographic of the character is important--the sex, the size, the race, etc--then that shouldn't be broken. I can understand that fans of Jack Reacher were mad because the character is based on massive size, though I didn't care because I didn't read the books. Peter Dinklage could never play Andre the Giant in a biopic. Casting Clancy Brown as Frederick Douglass would be unacceptable, as would casting Denzel Washington as George Washington. Will Smith couldn't play Tank Girl. And so on, and so forth.
Peter Dinklage is to Andre the Giant as Tom Cruise is to Jack Reacher.