[tlasjr]

For the most part for me it's the actor not their race that matters. I think it's easier for Marvel charecters as Marvel/Disney has complete control.
Hence we have both wite and black nick fuy's.

On the other hand look at G.I. Joe. Ripcord was white for more than 20 years. The movie studio decided to take the character and change the race and even what he does. No there is no white ricpcord.
And Roadblock, one of the a list characters, the hulking brute of the team who holds a browning 50 cal like an assault rife kept his race but became a ninja?

And yes, non traditional races changing can be a problem also. For example in the new Bay epic The TMNT will be aliens which means they are not mutants, not like related to terrestrial turtles and thus not trained in the Japanese martial art Ninjitsu.