Expanded Hair Customization

I've never posted in the EA forums so please forgive me if this topic has been covered (I did try to search for previous discussions on this topic to avoid duplicates). 

I think expanded hair customization would be a fun way to alter Sims. Specifically, being able to add highlights/lowlights, balayage, give Sims perms they end up loving/hating, etc. I know some styles have them built in already but we can't even customize the different hues used in those styles without changing the base hair color of our Sim and changing their hair color obviously has an effect on every other style used. 

Even if it's not a base game update, a pack of some kind where Sims can visit to get hair treatments that are preset and/or can be customized in CAS would be great. 

Again, if this has been discussed before, I apologize. I'm curious to hear the thoughts of others. 🙂