The Armoire is a great system; it lets you store vanity items individually from all the other stuff you might want to keep on your retainers, and it even organizes it for you. However, I noticed that several vanity items don't fit in the Armoire at all! For example:
Pre-order Mog Cap
Collector's Helm of Light
1.0 Garlean Goggles
Questline Garlean Uniform (body & head)
Halloween Costumes (the bodies; the heads fit in just fine)
Summer Swimsuits (three pairs of bodies and legs don't fit in, specifically)
FATE rewards (Behemoth/Odin gear)
And who knows what else.
I think it would be really great if the Armoire could fit all of that stuff in.