They could probably save space by having a single hairstyle have sub options with the variations. These could be invert options, going short, mid, long length, bangs/no bangs etc. As it stands now even the slightest mod counts a whole other hairstyle.

The customization options are obviously crazy outdated and would probably need to be rebuilt from the ground up. Not sure if that will happen in the lifetime of FFXIV but they definitely can release more hairstyles to accommodate, and slight mods are very easy to implement.