I wish they would bring back the iPhone 5's slate color. They have improved their anodizing process, so it shouldn't scratch as easily. That color was probably my favorite of all the available iPhone colors.
I wish they had different shades of dark colors, whether it's space grey and slate grey and whatever else, the same way they have silver/gold/rose gold for white faced iPhones. Really doesn't make sense to only have one dark option still.