Inspired by this thread:
It was proposed that maybe the late 23th (and early 24th) century uniforms -that were radical departure from any Star Fleet uniform before or after this era- actually were more formal class-A uniforms, and there existed a less militaristic looking class-B variant. So here is my suggestion for class-B officer's uniform:
I am not actually sure if I like them myself, anyhow, here they are.
(Based on uniform templates originally published in Star Trek: the Magazine.