*points up* This is a big part of why I view demands for race changes with a healthy dose of skepticism. In Hollywood, 'Diversity' is virtually always code for 'Black', usually 'Black Male'.
My take on race in casting is, like many things, its complicated. Some characters absolutely have to be a given race. Some characters don't, they can be any race. Some characters fall in between, where some race-swaps may be possible, while others aren't, all with varying difficulty for the writer.
There are also multiple reasons *why* a character might need to be a given race. One is core premise and story: Bruce Wayne is super rich New England elite from a long family line of super rich New England elite, he kind of has to be the WASPiest WASP who ever did WASP, with maybe a tad bit of Jewishness being allowable. One is representation, which is to say "There are few enough minority characters, don't swap the race of one unless you have a *real* good reason. Like being a racist stereotype." One is simple iconography: whether you like it or not, Superman is such an element of the pop culture psyche that his form is locked, and locked as a white dude.
If there's *not* one of these strong reasons to lock down a character's race, though, then you should feel free to change it, if desired. Of course, if the *only* reason you change it is for the sake of change, well, stunt casting almost never produces good results. Also, see above regarding "Diversity does not mean Black".