Bling of War: Except for the brief chunk of time that matched our Industrial Age, played mostly straight by the Imperial Legions. Beforehand, for much the same regions as Napoleonic (and previous) armies were quite dressy – well, that, and the giant steam clanks stomping around on the battlefield – and afterwards because big stompy Powered Armor with both noise and the ensuring thermal and neutrino emissions tends to make stealth something that happens to other people anyway, so you might as well go back to looking gorgeous on the battlefield if you’re anything other than scouts or special ops (who sneakily enough do have their own “field drab” armor which somehow never shows up on parade). And, of course, so long as the bling of war is on top of the fully functional deadliness of war and doesn’t interfere with its functionality.
This is, of course, completely unnecessary and not done by most people who advance past Industrial Age warfare – it’s just a local aesthetic preference. (The trope – which is still generally true in their universe – that the side with the shiniest uniforms tends to lose therefore has at least one qualification to it. That some people haven’t heard of said qualification and will fall right into the wrong assumptions isn’t strictly intended by the Admiralty, but they certainly don’t mind that it happens.)
Beauty Equals Goodness: Very much averted in one sense, even by local standards (see: Blue and Orange Morality) of goodness. It is perfectly true that the eldrae and the other Imperials are an extraordinarily Beautiful People. But by the same processes, so are the Renunciates. And so are the Renegades – even the Renegades who are very, very bad people indeed, by anyone’s standards.
Quite appropriate, really. After all, even fallen angels are still angels.
In another: yes, one of the qualities they esteem is beauty, as a form of excellence. But this does not imply, simple-mindedly, that the beautiful are the good. Rather, the dogma holds that it implies that the good deserve to be the beautiful, and therefore that beauty ought to be promoted by the sophont in those places where blind nature and random chance got it wrong again.
The Beautiful People: I refer you to the comments about “impossibly beautiful sexy immortal billionaire genius demigods” made under Can’t Argue With Elves. The engineering works, people. However pretty a people the baseline Eldrae alathis were to begin with – and they were – by the time autoevolution reached the very transsophont Eldrae kirsunar, it had gone Up To Eleven. The self-designated Supreme Eldrae and their cousin species in the Empire are self-consciously designed to be perfected, unflawed, soul-churningly beautiful, marvelous to behold, exquisite and/or excruciating in unsurpassed elegance.
(And if you’d care to sign up, they can do it for you, too. Queue for applications starts to your left.)
It’s a sort of inherited status, I suppose, inasmuch as you acquire it – most commonly – by being the offspring of an Imperial citizen-shareholder, although most of it is offered freely to immigrants and, well, anyone who turns up waving checks or cashy money at the right businesses… but since this does represent more or less the entire society, these Beautiful People do, at least those who haven’t yet earned their way into the investor-leisure class, have to work for a living, and many of those continue to anyway.
And yes, the surroundings also match (see: Emotion Bomb and Scenery Porn), because it’s not like they stuck to just improving themselves. Also played straight, again for almost everyone, with regard to the clothing (see: Sharp Dressed Soph), the housing (see: Big Fancy House), the wealth levels (it is a materially mostly-post-scarcity society, after all)…
Sharp Dressed Man Soph: Given just how obsessive the Imperials are about their ideals of beauty and excellence, the Empire has a heck of a lot of these (although not so limited to business-suit analogs). And most of the exceptions are found among the young, who sometimes tend more towards The Dandy instead – because while obviously these things should be taken seriously – clothing, like everything else, is Serious Business – they haven’t yet quite grasped how important making it seem effortless is.
The female version is essentially equivalent (although even less limited to business-suit analogs), but the young in this case tend to trend toward The Fashionista instead.
The Dandy / The Fashionista: Common among younger Imperials, who are pursuing the cultural ideals of beauty and excellence just as hard as they can, the more so to give them weight. (Looking awesome is an aspect, if far from the entirety, of being awesome, after all.) They do eventually settle down to a consistent, personal style, though.
Inhumanly Beautiful Race: Quite possibly, since the eldrae started out a very pretty people and have been engineering further in this direction for a long damn time; of course, it’s not like they aren’t happy to sell this technology on the open market in the interests of a more beautiful universe. (And, of course, assuming they don’t fall directly into your Uncanny Valley; the trouble with being a product of postsophont genetic engineering is that you look like a product of postsophont genetic engineering. This troubles the eldrae not at all, but your awe/unease/horror/fear may vary.)
Perhaps, if it turns out transhumanism (or, rather, its polyspecific analog, transsophontism) is the development path all species end up taking once they have the ability to do so, the problem is that once they’ve spent much time and effort on engineering themselves into ever-more brilliant and beautiful forms, they rest of the universe becomes simply too unbearably stupid and ugly to interact with…
And so they don’t.
And they become pretty damn good at hiding from SETI searches, too, because the last thing they want is any of these ugly morons turning up on their doorstep.
Simply revolting, sweetie.