I really like your idea, and I agree that standard uniforms should have a less-militaristic look to them. Here's an additional idea: maybe Class B and lesser uniforms should use a simpler, less ornate badge design more like TOS.
Agreed, I think the version used in TMP would work fine.
Maybe you could also borrow an idea from current U.S. Army fatigues by incorporating rank insignia onto the chest of the jacket, maybe on a small flap that would cover the upper part of the zipper.
Ugh. I hate that rank on the chest design.