Allow people to write their own hair colour
When filling out your hair colour, there is a drop-down menu. Blonde, Red, Brown, Black, Hairless or Other. Well, at the moment, my hair is black with red streaks. Ot one time, when I was in uni, it was blue. One of my friends has pink hair. Lots of girls have pink hair! And what about people who want to describe their hair as auburn, chestnut, strawberry-blonde etc? Hair is an important part of some people's identity!
I realise this would make it impossible to search for a sexual partner via hair colour, but who would be so shallow as to want only to meet people with a certain colour of hair?!