I find the concern over individual expression to be.... interesting. My dc are pretty creative with their clothes. Their closets are full of clothes that they have deconstructed/reconstructed and sewn, patched, dyed, stenciled and otherwise embellished to ensure that they wear one-of-a-kind items. There is a shelf in the bathroom devoted to hair dye with a full colour spectrum from bright pink to deep purple. Yet, they didn't make any fuss about wearing uniforms. As I wrote upthread, they were not enthusiastic about it but they recognized that there were a few advantages and made the best of the situation.
In some ways, I think wearing the school uniforms made it easier for them as they moved into various situations entering young adulthood. DD wears a uniform for her volunteer work at the local zoo. DS works in a retail shop and is expected to dress to a certain standard. They can adapt as necessary for whatever environment they find themselves in. Since they are both performers at heart, I wonder if they approach uniforms and dress codes as akin to costumes and camouflage. All I know is that I'm actually grateful that I don't have to listen continuously to grizzling about clothes. They wear what they need to wear and get on with their day.