Róisín - hello, fellow Vorkosigan Saga fan! Yes, this was one of the books I've been thinking about when writing about clothing. Good examples.
Asterales - I know that annoyance at "because it looks cool" exoticism, but I think much of the problem with it stems from the fact that the writer is going for pretty looks without considering whether something like this could reasonably develop, or what the practical implication of such clothing, hairdo and others are. A good example would be Jane Lindskold's Firekeeper books. One of the cultures there has a "thing" of wearing complex face-paint, Polynesian-esque face tattoos and heavy, ornate robes. In this case, it's not explained, but this serves the story itself, as a huge part of the mythos is that people are descendants of old colonists whose original cultures are virtually unknown. However, Lindskold uses the exotic cultural trappings in many different ways: a character is shown to be adopting the culture by starting to wear robes and face-paint; the MCs are instantly noticed everywhere they go because they dress too lightly; a character running away from the culture has troubles disappearing because of his tattoos; and of course a girl wearing comfortable trousers catches up with member of the culture running away from her in no time. So I'd say there's nothing bad in exoticism itself as long as its implications are considered and applied.
Unwary - yes, I do have one such crocodile. Some half a year back, I've made a world where I had everything figured out. And I do mean everything. I had all the species described in detail, including cultures within them, biological stuff, longevity, social castes and relationships with other species (a friend of mine said my "dwarves" don't deserve the name, as I tried to figure out "biologically correct" humanoid with dwarven "qualities" and it ended up as an amphibian with sharp claws, pale skin, no beard, gecco-like fingers, huge eyes and a third eye on the forehead, glowing infrared. Likewise, elves ended up having talons-like nails, empty bones and feathers on their heads and backs). I had international politics, all the countries mapped out, rough political situation in all of them, seven different religions and a magic system I could perfectly understand. I had history, cults and secret societies. And when I tried to put all this in one "master file" for quick reference, I clocked at 50 pages written in font TNR 12. And I wasn't finished.
It was about this point that I realized I'm not writing a novel, I'm writing a bloody RPG corebook, and I still didn't have good motivations for main characters or any sort of coherent plot. So right now, the whole master file is sitting on my computer and pendrive waiting until I either become a good enough writer to tackle it or decide to turn the whole thing into actual RPG, because it'd be, honestly, a pity if all that worldbuilding of mine was to go to waste.