At the very least people would be upset about the demoman's VA being white, and would probably try to claim that the demoman being an alcoholic has everything to do with racism and not the fact that he's supposed to be a Scottish stereotype. Tbh, other than that I'm not really sure what people would get upset about except maybe that there aren't any (known) playable female characters (iirc the pyro's gender is supposed to be androgenous and a mystery) and 8 out of 9 of the characters are white.