There are quite a few - even more if you accept far future human cultures as “alien.” C. J. Cherryh has written much of her best material from an alien perspective; for example, in Pride of Chanur the viewpoint character and most of the other protagonists are non-human, and the only human with a major role in the story begins by being mistaken for an exotic animal. Many of Hal Clement’s books are written from the perspective of an alien culture; in his books, usually very alien, since Clement specialized in imagining biospheres very unlike earth. Lots of other examples, some of them very good.
In Star Trek: Voyager the Kazon were divided into a bunch of different, often warring “sects”. Although granted, from what I recall they all seemed like pretty much interchangeable tribes of nomadic space barbarians.
The alien invaders in Larry Niven’s Footfall had political fractions - complete with open debate about what actions to take, some deal-making, backstabbing etc. - and what is more, the invaders came to Earth because they themselves had been exiled from their homeworld following a political/religous schism.
Also, the Moties in Niven/Pournelle’s The Mote in God’s Eye had political entities, wars, negotiations and power-broking. (Interestingly enough, they also had a caste system with physical differences between the castes.)
The Daleks come in Imperial and Renegade factions these days … both will exterminate you as soon as look at you, but there are distinctions between them …
Actually, come to think of it, Doctor Who has its moments when it comes to alien politics. There’s a fair amount of in-fighting and back-stabbing among the Giant Spiders of Metebelis 3, or in the Imperial Court of the Draconians (there’s another reptilian race who, by and large, aren’t jerks) … one plot point in the recently released DVD of The Leisure Hive hinges on a political conflict among the alien Foamasi … there are, definitely, several different kinds of Cybermen (someone in Tomb of the Cybermen even assigns the design of the tomb to a particular Cyber-historical period) … the Ice Warriors and the Silurians both have internal politics … hmm. I’m not saying that Doctor Who is a triumph of stark realism, here, but it’s got its good points.
On an unrelated note; the Chasch in Jack Vance’s Planet of Adventure series are culturally and ethnically divided (into Blue, Green, and Old varieties, each with its own culture).
For that matter, consider the planet Mongo in the old black-and-white “Flash Gordon” serials (hardly a triumph of realism!) Granted, they’re portrayed as different races; but on one planet you’ve got the Emperor Ming’s court, Hawkmen, the Clay People, and I forget how many others.
I wonder if one could actually argue that a dependence on monocultural aliens is a more recent cliche, most frequently perpetrated by script writers who are under the impression science fiction is so easy anybody can write it?
Now that you mention it, it does seems like the aliens in older works are often more complex than their more recent counterparts.
I wonder if Star Trek could be largely responsible for creating this cliche?
Oh, and I don’t know how I forgot this earlier, but another nice race of reptilians: The Drac from Enemy Mine. Of course, most humans assume that they must be eee-vil because of their alienness, and the story starts with the Drac and the Humans at war, but it turns out that there’s no good reason for us to be, and they’re just as innocent as us (not very, incidentally).
That would be plausible. In part, because the “seeking out new worlds” format meant that writers would often have only one episode to introduce a new species, describe it, set up the problem, and resolve it. In those circumstances, I could imagine a more diverse planetary culture being only confusing.
In any event, it does seem that many people’s experience of “science fiction” consists largely of Star Trek. There continues to be a lot of writing out there with much more depth to its aliens, but it isn’t as familiar.