They've been there since the beginning of the game, were converted from equipment into costumes later, and I've actually grown to like them. But, cosmetically, they've needed some serious love for a while. I'm referring to the Tactical, Science, and Engineering generic kit costume pieces and the Alpha, Beta, Gamma costumes in the character creator.
The biggest complaint is in the Alpha-Beta-Gamma armor costumes. The ultra-shiny copper appearance on the Alpha variants has been crappy looking from the start. The launch of Mirror of Discovery saw the ugly orange shine removed from all of that, and while it was a bug that screwed up many other outfits, I'm requesting that the generic armor costumes have that reinstated. The orangy shine makes it extremely difficult to actually have any seriously diverse color options for the armors, since just about all of them simply fade into a copper look as soon as any light is put on. The kit costumes have the same problem on several of the pieces, only to a slightly lesser degree. Still, it's utterly pointless for you all to have any kind of color selector for those things if all of your color choices are turned orange by the texture of the costumes. I expect you all weren't intending to pull a Henry Ford here (you can have any color you want on your armor and kits, so long as it's a fugly orange shine), but that's what you have right now.
While that is my main complaint and the one I seriously want fixed, I would also suggest that the different variants be slightly less restrictive. It actually wouldn't be half as bad that the Alpha armors are all orange if I could apply the same glow strips and color configurations to the Beta and Gamma armors. Which I can't.
Lastly, I suggest that all generic armor and kit costume pieces work entirely under the same color palette, rather than be faction specific. You certainly can make a compelling case for why all the different uniform items don't all share the same palette, since they are different materials made by different aliens for different reasons. But the generic armor and kit costumes are exactly that: cross-faction cosmetics that everyone can wear. It's about time that they were treated that way.