From my understanding, ID mechanisms through blood & prints, as a Forensics skill, is specifically gated behind tech only available to the WJF. Forensics-skilled PCs not aligned with the Hall, specifically, can only check corpses for Forensics analysis. If that's true, this kind of change would make it so any attacker would be able to commit a crime, pop in for a change of their entire body's appearance, then disappear. I agree with Mindhunter, I think there should be one constant. I'm fine keeping skin-tone unalterable.