Akira Toriyama at one point said Trunk's hair was always supposed to be blue. That there was some type of confusion or mistake that had his hair be portrayed as lavender in the first place and that is why the color ultimately changed. He wanted it to meet his real vision.

This is the exact type of thing that turns me AWAY from games. It starts feeling like a responsibility rather than fun if I have to do it everyday or be punished. What I do want from the games is to bring back personalities in the villagers. Some of them were even mean to the player but it was much better than this cookie cutter dialogue we get from them now.