You all aren't thinking big enough!
I think we should be able to dye our hair at the existing outfit station, and at a minimum we should be able to choose between all available hair colors. Bonus if we could use all available unlocked dyes.
I think we should be able to apply all of the colors just like we can swap around the adornments. I don't want to have to obtain a few colors at a time via a pack!
In a game where we can change our skin with the click of a button, being able to do match our hair to outfits and skin with the same ease is long, long overdue.