The plan right now is to roll out an extra Uniform slot for Klingon Empire players at the same time we unlock the Off Duty slot for Feds.
While I'm happy to always get a new costume slot, right now at least for females on the Klingon faction there really isn't anything else to wear in those extra slots for us. We only have 1 top (with 2 options to it, one armored the other not so armored), 1 belt, 1 gauntlet, 3 pants, and 1 boot options. At least males have 4 different boots, shoulders, 2 belts, and 2 distinct tops to make them semi diverse. I guess we could just create 3 different colored versions of our same uniform, but that's no fun. :p
Are there any new costumes coming for Klingon faction in the near future? I admit it really irks me that the Klingon, Orion, Gorn, and Nausicaan NPC's have far more diverse costume options than we players of those races do.