If not Vanity slots, I don't see why we can't switch stats from one piece of armor to another via synergy.

For example, if you enjoy looking at your Doublet, but really want your Goetia Coat+2 stats, you can transfer the Goetia +2 stats from the coat to the doublet, and the doublet's stats to the coat. Would also need to change jobs that can wear it to match what the initial piece of armor wears and vice versa.