If you could customize / personalize your ship's design, you would stand out from the crowd and people would be able to see the difference between ships. This could lean both ways, whether it is a good addition or not.
As for personal uniforms / customizing your character, I would love to see a color-variety of the different clothing-sets. I like some of the sets very well, but when they're limited to one specific color, some of them don't look that great.
People love variety! (I love variety!)