It would be nice if we could explain the costuming of "The Wounded" as simply as that. Alas, DS9 gave us plenty of flashbacks to timepoints preceding "The Wounded", and everybody there wore the same stylish DS9 gear instead of this early armor.
Wellll...apparently we've also got THIS Mr. Photogenic winner to contend with as well, from the episode "Ensign Ro."
And yes, I am being VERY sarcastic.
So either this is a short-term experiment on Central Command's part that failed, or there's something particular going on with whatever Order Macet and Dolak were in?