Re: Why is command wearing blue?
I always found the constant change in uniforms pretty ridiculous. How many times do uniform designs change in real military?
Voyager was the only ship that had the same uniforms for 7 years, and that's just because she was stranded in the Delta Quadrant. Picard's Enterprise(s) went through 4 uniform designs in 8 years. They even had two different uniforms scattered randomly across the officers at the same time in Generations, which is the peak of unbelievability, I guess.
Trek is entertaiment, so when it comes to costuming the real world need not apply. The concerns of a TV show or movie is different than that of a real military.
TOS had four different uniform types (five if you count the pilots) The black collared shirts, jump suits, dress uniforms and the wrap arounds. It wasn't unusual to see two types together. I think the second TNG uniform popped up on DS9 from time to time. So I look upon the DS9 uniforms being in the same "group" as the TNG ones. Sort of like when my dad was in the Aiir Force. He usually wore his kahkis, but on occasion he would dress in his blues or fatigues.
The boring one, the one with Khan, the one where Spock returns, the one with whales, the dumb one, the last one, the one with Kirk, the one with the Borg, the stupid one, the bad one, the new one, the other one with Khan.