It'll probably be like WoW where using a model viewer just gives up a barbie mode. Honestly I am curious as to why they went thru the trouble of adding an undergarment model to the game. More that they actually have a slot for it. Usually it's just pasted on. It may be for undergarment changing options. For example switching it out with swimwear. Would allow you to equip armor over it without the need to keep changing it. From my knowledge I think FFXIV was supposed to be a little more mature than FFXI was. I can't remember where I read it... Anyway even if the garments don't come off I don't care, the fact they at least aknowledge the garments as something other than plastered on parts is good enough for me.
FINAL FANTASY XIV Roleplayer
Sair Gammonari - Hyur Midlander Male - Conjurer (Somewhat retired.)
Mihana Zhralyia - Miqo'te Seeker of the Sun Female - Archer