One of the massive areas of appeal for me in GalCiv2 was the ship designer. I loved the feel custom-designed ship aesthetics could give an empire, and it gave the game a massive amount of replayability. However with the way the unit designer functions it is very hard to make unique-looking soldiers without sacrificing combat ability. With my personalised Wraith empire I've taken to sacrificing the torso armour slot and using black robes instead of armour, just so my troops look unique. Even things like cloak slots end up getting taken up with magical equipment.
While this is one solution, I'd prefer if there were some other ways to give troops interesting looks without compromising too much on effectiveness. One obvious solution is for there to be a variety of options available for the appearance of various armour and weapon types (possibly in a drop-down menu to avoid cluttering up the design pages), but even if this is just different textures, it would take up a fair bit of manhours to produce.
Unfortuately, all this thread is really for is to express my personal preference in this area, as I don't really have a foolproof solution.