Our personal preferences on style or the color palette are irrelevant as far as the concept goes, since they are future uniforms and about the only thing we can be sure about them is that they would look a lot different from our present day aesthetic expectations.
I respectfully disagree about style and color preference with concept, because Star Trek is first and foremost supposed to be entertaining fiction. Otherwise, the majority of designs in Trek don't make much practical sense, like the 90s trend to make starships more streamlined (warp "aerodynamics" was just a backdoor concept as an excuse to make them sleeker) or the dustbuster phasers that would be bad for aiming. But it's part of the package and helps sell what we're looking at as the future.
Keep in mind, I'm not saying that practicality doesn't matter in design or that it's impossible to reconcile that with aesthetics. It's just that I believe if the uniforms look boring, and you're going to be watching the central cast for the vast majority of the movie and they're wearing the uniforms, then they themselves lose a bit of energy. If TMP is considered the "slo-mo" picture, I would think the uniforms play a role in that -- not as much as the editing or pace, mind you, but adding to an atmosphere of dullness.
The movie uniforms were a victim of the 70s aesthetic -- muted, beigey loungey type of feel. I was watching the first Anchorman movie and, while a comedy, Ron Burgundy's color choice isn't too far off from the browner uniform colors. And the worst way to date a futuristic movie is to use fashion trends of the decade in which it was made.