I think it would be pretty neat if you could only get a certain style of hair if you grew it long enough and that it cannot simply be aquired by choosing it from menu. Ofcourse all hairstyles in my opinion should be available from the first customization options.
The same goes for facial hair in my opinion.
Tattoo's should be changable whenever you want them to. But only in tattoo parlors.
Scars should be unremovable. It's just not realistic if you can altar scars.
Discuss.