Cultures in Fantasy Novels

While writing my first fantasy books I have been fully conscious of the fact that the great J.R.R. Tolkien was slammed quite a lot by critics for his fictional cultures being a bit too homogenous. When he did have dark skinned races, they always showed up as dragon fodder in the bad guy's armies.

In my world the tribe that became the Greatlanders and occupies the Known Lands became different from all the others because they welcomed the arrival of a ship from Earth (rather than responding with fear or attacks as other tribes did), so they gained the benefits of what the Earth scientists were willing to teach them (the wheel, stirrups, etc.) while other tribes languished in relative barbarity. Eventually these other tribes banded together and drove the advanced tribe away, which is when they found the sheltered land that they now call the Known Lands.

The problem is that this leaves me with a kingdom that essentially has a single race. I run the risk of having critics roast me the same way they did with Tolkien. I do use the barbarian tribes to the east a bit, but the ones who live nearby are relatively similar to the Gauls and Celts of ancient Europe, so they don't help me a whole lot as far as diversity goes.

In my second book, I have been toying with the idea of including a couple of characters from far to the south, an arid plain where the nomadic tribes are olive skinned and of a very different culture to the Greatlanders. The problem I am having so far is that these characters don't have a natural part within the storyline as it currently exists in my head, so I would have to enlarge and complicate the story to make them fit. I don't think it is a huge issue, as once I start to write them in, the story will naturally change to work with them. But, it does make me wonder about our politically correct atmosphere these days. Have you ever altered a perfectly fine storyline just so you could stave off any potential criticism from the PC police? Have you forced a strong female role into a storyline, or made some characters fit into racial types that aren't your own even if the story didn't need it?

I see a lot of good in making people be considerate of racial and sexual issues, but I admit to some trepidation about overdoing political correctness. If, say, a Mongolian writer wrote a great story about Mongolian society, we would laud him or her and never dream of saying that he or she must include other races in the story, yet if a writer is white then he or she is almost expected to have to do so. This is what has always bugged me about the critics of Tolkien. It seems natural to me that most people are interested in writing about their own cultures. I am certainly most interested in European-type cultures, because my family background is English and German. I have some interest in other world cultures, but they don't resonate much with me when it comes to my writing. I read a book now and then about non-European cultures, but the ones that I really love are always about ancient Rome or England or the Middle Ages in Europe. I don't feel I should have to apologize for being most interested in my own ancestral history.

So, will I use these nomad characters? I think I will, if I can make the story work. If I can't then I will cut them out. What about you, has political correctness ever affected your writing?