When you create a character you can choose your player color, the color of your default armor/helm, and the style of your default armor/helm. I'm not entirely sure it'd be a good idea to let players change their player color, but being able to change the Spiral armor color and style would be nice! Dye sets for other armor would be nice too but I could see why that wouldn't be included.
I could see changing your Spiral armor color or style costing like, 50-100 CE.
Don't see what's wrong with letting you change your color.
Honestly, it seems kind of silly that you choose your PERMANENT color before you ever get a chance to experience what the game has to offer. I mean, it makes you make a blind choice which just seems ridiculous. I even considered crafting all my 5 star gear at once, then making a new knight in a different color to wear it....but i'm lazy. And most likely in 2 months i'd be no happier with the new color. I'm currently green, but can't help but think purple Mad Bomber helm and bomber armor would look great.