Well, I think the key is that a certain stereotypical view of the "proud barbarian" was inherent in the script, whether Orientalist or otherwise, so probably casting anyone other than white actors -- or a mix of ethnic types -- would've ended up giving a stereotyped impression. While it was a nice idea to try to break the pattern of only casting white people as aliens-of-the-week, they should've chosen another episode to do it -- maybe "Justice" or "Haven." (Although the fact that the people responsible for casting chose
this episode, the one with the "exotic Other" stereotypes built into it, as the one to feature an all-black alien race, and kept other first-season TNG alien races all-white... well, that suggests something about the people responsible for casting. But at this point, the producers were mostly veterans of TOS, so they were from an earlier generation and had certain assumptions that would've been hard to unlearn. On the other hand, they did cast Michael Dorn as one of their main regular aliens... but then, TOS Klingons were kind of a racial stereotype themselves, essentially Space Mongols.)