In 1978 Carl Sagan told Johnny Carson the big problem with Star Wars: "They're all white"

Carl Sagan appeared on The Tonight Show in 1978, a year after the release of the original Star Wars movie, and befuddled the audience into silence when he complained that the movie was preposterous because life on another planet would not have evolved to produced human beings. 

Star Wars starts out saying it's on some other galaxy, right? And then you see there's people and starting in Scene 1, there's a problem, because human beings are the result of a unique evolutionary sequence based upon so many individually unlikely random events on the Earth.

In fact, I think most evolutionary biologists would agree that if you started the Earth out again and just let those random factors operate you might wind up with beings that are as smart as us and as ethical and artistic and all the rest, but they would not be human beings. That's for the Earth. So, another planet, different environment, very unlikely there'd be human beings. It's extremely unlikely that there would be creatures as similar to us as, the dominant ones in Star Wars.

Sagan then goes on to complain that the humans in Star Wars were "all white":

The skin of all the humans in in Star Wars, oddly enough, is sort of like, like this. And not even the other colors represented on the earth are present much less greens and blues and purples and oranges

When Carson pointed out, "They did have the scene in Star Wars with a lot of strange characters," Sagan replied:

Yeah, but none of them seem to be in charge of the galaxy. Everybody in charge of the galaxy seemed to look like us. I thought there was a large amount of human chauvinism. And also, I felt very bad that at the end the Wookiee didn't get a medal also. All the people got medals and the Wookiee who'd been in there fighting all the time, he didn't get any medal. And I thought that was an example of anti-Wookiee discrimination.