[hasbroherofan]

Me personally, my litmus test is does the change actively hurt the story in any way. For instance: Tony Stark building Ultron instead of Hank Pym did not negatively impact the storyline in any way for me. Nor did Bucky Barnes being an adult soldier instead of a little kid with a costume (though Brubaker's retcons had been veering in that direction anyway) or Hawkeye not wearing a purple spandex costume.

There are actively instances of changes hurting the film however: Galactus being a cloud, Doctor Doom being a wimpy businessman, Dick Grayson being played by a grown man (thus calling into question why Bruce would adopt him in the first place), Barakapool, Baron Strucker being a wimpy scientist, ect. Changes like that usually affect the film by either wasting a character needlessly or greatly robbing them of their menace.

For me, Domino falls squarely into the former. There's no world where I can reasonably say Domino being a black woman and having an Afro harmed the film. In fact she was one of them most consistently praised aspects of the movie.