Actually I completely disagree about the uniform subject. Scorpy is wearing a custom designed cooling suit, one that he had subltly altered with body armor over time, not something issued to him by Peacekeepers. For one thing, he kept that fact a secret from most people, only his close associates knew the 'rumors were true' about him needing a cooling suit, [altho he adored freaking out Braca with it] and none of them knew about the armor unless they'd witnessed Scorpy survive an asassination he shouldnt have.
Scorpy, being an evil genius, and working with people like Natira, accumulated a fortune on his own and surely used it to keep himself in style. Scorpy made himself so powerful that he is allowed the priviledges of rank, which if you are high enough, you dont need to wear the uniform. From what I understand from Kemper, Scorpy actually made himself powerful enough not to need a rank at all, he is simply Scorpius of the black ops wing of Peacekeepers. Something more than a disrupter, something less than an Admiral, his speciality is manipulating everyone to make himself indespensible, and leaving no doubt that anyone should fear results of disobedience of his orders over any niceities of rank. Look how he simply removed Crais from his own ship.
Grayza also never bothered with a uniform, as that would involve covering her sweaty boobs and obviously she felt powerless without them.
Later she finally felt she could cover them when she had the exposed belly of the PeaceKeepers ultimate leader's baby (supposedly) as her sign of power - thank goodness, it did at least make her look like she had a braincell at that point. Partially I guess, because, for all the show, we all knew it wasnt really that guy's baby. Big digression, but my point is, no nincompoop designed a uniform to expose a baby, that was obviously a fashion design that she chose to wear instead a uniform, to show off her source of power best. And the lovely tattoo, of course.
*pointless digression to follow*
The more militant the lifestyle, the more the higher rankes can abuse their privledges without being questioned, was the general idea - in the Peacekeepers you wanted to have friends on the High Council to be a mover and shaker - Bracca was certainly rising smoothly to the top by siding along side the movers and shakers, simply standing next to a much bigger target to rise with their successes and glide on over the victor as they met failures. Bound to be well thought of by the High Council by the time he becomes Admirial. He, of course, will always choose to wear the uniform, because it is the source of his power.