I know this is an idea that has been brought up countless times before, likely a common suggestion, but that's exactly why I think it should be considered here. It comes up all the time in my LS's, someone will mention that after a year or more of playtime they're tired of their characters hairstyle or etc and what to change it.
This doesn't have to be entirely complex, or even hard to implement. How much effort would it take to put in an NPC that you talk to, pay about 10k gil or so, and get to repick from the already present list of appearances. Not allowing you to change your race or gender, just the appearance and maybe your size.
I know i'm tired of looking at my Tarus grey ponytail.