Don't know if this has been suggested yet, and I honestly want it purely for cosmetic reasons.
It would be nice if we could change our character's race or gender. I've played other MMO's that allowed this through the purchase of a ticket in the cash shop (in this case it would be in the AC shop).
I honestly wouldn't mind paying for it either since my reasons are purely cosmetic. However, the ticket should give us a window of time in the salon where we can change our character's proportions for free, I feel like this is obvious. Or perhaps the first time you visit the salon as your new race/gender.
As for outfits and the likes I think they should be left out of the equation. This is a conscious choice of the player, some outfits don't have options for the opposite gender, not to mention CAST parts. Let's not make this more complicated than it is. If you want to change race/gender be aware that some of your past cosmetics will no longer work for you.
Right now I'm feeling really torn since my main is a Human, but I suddenly decided I wanted Elf ears. Which made me create a new character. However, I don't like managing more than one character so... It has reduced my game time significantly... I don't see the point in investing cash in the game either now since I don't feel as connected to my character anymore, while before I had planned cash purchases for mags, storage, etc. Now they feel... Not worth it to me. My interest dwindled, something that would have been easily solved if I could simply pay to change my race.
I ask you to please consider this SEGA. It would be a really nice feature, you'd make money off of it, and players like me that dislike having alts but enjoy changing their looks freely to full extent would be very happy.