Abrams was concerned because Cho was Korean-American and not Japanese-American and Abrams thought it might become an issue with fans.
Assuming fans even can tell the difference between a Korean and Japanese surname, why would they care, after decades of accepting human actors playing aliens, robots and interstellar dieties?
That attitude always throws me. Actors are paid to act
. It is their job to pretend to be what they're not. But to think of Star Trek fans being narrow-minded bigots is the strangest thing of all.