They don't have to make any new class or something so complicated. If/when they add more character creation options they could provide everyone (all characters that at that given time exist) to edit their character one time in character creation for free.

After that perhaps never, or it could be an option to do it for a small real life fee.

In Aion they have this feature, a cosmetic surgeon. It will let you re-edit your character in character creation screen. And so they have added more options and hairstyles (yes cause they 48 or something they started wasn't good enough.. lol) as the game has aged. I think now there is up to 60 hairstyles