I know we're not really meant to repost already existing suggestions, but the ones I've seen from a quick keyword search are either one sentence wonders or a decade old. I thought it'd be a good idea to create a fresh thread with a more fleshed-out version of the idea.
I think a Hairdressing/Barbering skill would be a great addition to the game. It would allow players the freedom to customise their hair without completely removing the use of the Hand Mirror. Hairdressing/Barbering would also open up a lot of potential for player interaction and roleplay depending on how it's setup. I also think the random appearance when you first spawn and the Hand Mirror should remain the same, not adding any of the new haircuts or colours to them, to incentivise the training and use of the new skill. Apart from adding new hair/facial hair styles, I think a lot of the things that would be involved in making this a skill are already in the game. I'm not saying this would be easy, there's obviously going to be a lot of back end work to make it happen, but it'll surely lighten the load if this skill does go into development.
How it could work:
You would use a pair of scissors on another player, this would open up a prompt for the other player which they would have to accept/deny (similar to dueling), if they do accept then a window (similar to the Hand Mirror window) would appear for the person who used the scissors allowing them to customise the other player's hair. When the hairdresser completes the haircut there could also be a further window that appears for the player receiving the haircut where they consent to the changes (to avoid griefing). There is also the potential for dyes to be used to change the hair colour which would open up a much wider variety of options for customisation.
For those who want to cut their own hair, a mirror would need to be added to the game which they would use scissors on to open the Hand Mirror-esque window allowing them to customise their hair. Since cutting your own hair is arguably harder to do, it should require a higher skill to perform that specific haircut on yourself than it would to perform it on another player.
Finally, so the skill doesn't solely rely on player interaction or spam cutting your own hair, there would also need to be some sort of training dummy-esque item added to the game that allows you to train your skill on it. This could simply be made by combining thatch or strings of cloth with a training dummy, which would add 'hair' to it. As your Hairdressing/Barbering skill increases you would unlock a wider variety of styles and possibly a broader RGB spectrum for dyes.
Please avoid responding with +1/-1 as the devs ignore those kinds of comments. Instead give feedback or possible additions to the idea, thanks