As for "Space Nazi's", no I don't like having them in SF-series. First of all, it's really unrealistic that there should be Nazis with swastikas and all that on other planets. Nazism was an Earth bound ideology from the 20th century. I find no logical explanation why it could have been spread to other worlds in space. I can imagine dictatorships and opression on other worlds but in that case they will be a lot more different than those on Earth. And if we should have "Space Nazis" why not "Space Commies" too. In fact, Communist dictators like Stalin, Mao and Pol Pot were actually ten times worse than Hitler and his gang when it comes to mass murdering and genocide.