Never saw the need for this feature in any MMO I've seen it in, and don't see the need for it in XIV, if you want the look of wearing a certain item the solution is simple; just wear it?
Then when you go into battle, simply equip whatever "best in slot" gear you want.

Last time I checked this was a mmo RPG, not Second Life...

Personaly I'd rather time be spent on making actual content, new gear, new features, fixes of currernt issues etc, then to have a feature which we already have a function to emulate in game atm.