They're basically something like a cross between medieval and Napoleonic France, with some of the trappings of the Roman, Holy Roman, and Russian Empires. Their agriculture is all privately owned ("peasant proprietorship"), their industry is regulated by committees of craftsmen who own their means of production (basically guilds with a few differences), and their government is by military officers who still have many of the trappings of feudal lords, under a single executive. Their chief religion (they've got more than one) is centralized, sacrificial, and monotheist.
But I don't think mine qualify as a Sue, and I'll list the things I did different. And I do mean list.
- Embroider this in your skins, writers, NO NOBLE SAVAGES. I don't care what they taught you, most of the Native Americans the US actually had wars with were somewhere between Vikings and Mongols on the SOB scale; if Comanche had a word for Karma it'd be "smallpox". Yeah we treated a lot of peaceable tribes badly—and didn't treat the Comanche badly enough (personally, I think if horse-nomads don't steal your corpse's head just to be sure you're really gone you're being too nice to them)—and there were excesses in the wars themselves, but don't let's pretend all the bastardy was on one side. It wasn't, not by a long shot. African tribes are the same story, as were the European barbarians, let's be real clear—romanticizing the Vikings or the Wends is just as much Noble Savage BS as romanticizing Plains Indians or Zulus.
My aliens not only have higher tech and science than humans, they have a state, with formalized laws and a concept of government based on abstract principles. Because sorry, the alternative just doesn't work as well. - Similarly, no Proud Warrior Races. This is just a personal thing, but I hate that word "warrior"; "soldier" is so much more civilized. A soldier is a professional, a warrior is an amateur—and amateur war is a scary thing. It's not a coincidence that Proud Warrior races usually use about 2/3 of the Noble Savage cliche, even if they have space-level tech. Or they just combine them, like the Na'vi do. Also like the Noble Savage thing, they ignore the bad side of that sort of culture.
Which isn't to say militocracy is a bad idea—many societies are ruled by their soldiers, with no ill effects. Sure, military-dominated states currently tend to be bad, but it's not inherent; it's just that all the decent governments, currently, are in a tradition that taboos militocracy. It's like how, in much of Mexico, only loose women dress as revealingly as American women do—that doesn't mean dressing that way makes you loose.
My aliens are a militocracy—the political leaders are also military officers—but the officer class has a number of restrictions the citizens don't, analogous to how you have fewer civil rights in military than civilian law. They also use their peculiar, mystical code of honor—essentially chivalry—as a political ideology. The fun thing about that is, chivalry precludes doing certain things even to an enemy, and applying it systematically, as the ideology of the whole state, means their state has self-imposed limits, like a Constitution.
Rank is hereditary, but that just means the children of an officer automatically have a commission—they're raised with that in mind, the funny thing about having an elite with a specific job is, you can raise it to do that job. Anyone can be promoted from the ranks, too, and it's pretty easy to lose a commission. - This is probably the most important: make them work at it. America has to be continuously maintained by human sacrifice offered to the Tree of Liberty—it's funny how innocuous Founder quotes sound scary if you rephrase them—and any alien society would constantly have to fight threats from within as well as without. Any functioning ideology will require striking a balance, and there'll always be someone who figures he'd be happier under some other balance, even if the whole rest of the system falls apart. Some people are willing to do very bad things to adjust the balance, and that needs to be shown.
On the other hand, it really is Sue-ish if the only conflict or crime is people trying to buck the society's system. I mean, what, so the Na'vi are so perfect they even accept being cuckolded with nary a grumble? Riiiiight. Sorry, but no species whose males have so little in the way of gonads could ever win a war—and it's unrealistic, also, in that Neytiri's clan would probably have lost the support of Tsu'tey's clan for something like that.
My aliens constantly have to put down secession attempts by their officer class. See, once, all the nobles were supreme in their own territories, but then they were gradually absorbed by the "Empire". Some of them want to be supreme again, and are willing to do many very bad things in order to secede. On the other hand, though, they also have normal crime and conflict—the main alien character is a cop, after all. - Don't just show them working for it in the here and now, though, show how they've had to work for it in the past. Obviously tread carefully, or you'll end up with an alien messiah story, but I expect to know, you know, how'd they get their one-world government, or that sort of thing?
My aliens were consolidated by a huge war between two branches of their empire, that killed 93 million people in 95 of our years. But that was their whole species fighting—World War II was only in the Eastern Hemisphere, mostly the north half, and killed 70 million people in 6 years.
The aliens also had a reform, 88 of our years before the big war (so only in one branch of their Empire), that made the people, rather than any other officer or even the Empire, the recipient of the officer class's fealty—remember, the officer class still has the trappings of feudal nobility. Similarly their women's status has been steadily improving, mostly due to their religion, which was also responsible for chivalry (Christianity, especially the reverence for the Blessed Virgin, was a major factor in the incredibly high status medieval women had, and in the creation of chivalry). But the aliens still have sexism and over-ambitious nobles/officers, because societies aren't perfect. - This is a rule for avoiding Sue-ishness in general, actually: if you don't want to show them doing something bad, you still have to show them being tempted to. Unless you're writing a story specifically about a race where the Fall never happened, a la Perelandra, your aliens still have to have that tendency to evil.
My aliens' emperor admits, in the third book (in the works), that he had one of his aides calculate how long it'd take to genocide the human race—he overreacted to reports of atrocities humans were committing against them. He never did anything, but he did actually want to vitrify every planet humans lived on.
Incidentally, the answer was 144 of their days (slightly more of ours), assuming human space resistance was at its maximum. It sounds even more pitiful in their units: two months, two nine-day-units-analogous-to-weeks.