For Iuitl, for instance:
Iuitl Headgear - Better than Uk'uxkaj Cap for TP/(some WS) when augmented properly, but not that much better.
Iuitl Vest - Probably worse than Manibozho R15 for most WSs, although maybe not now that the skill update hit and attack is much less important.
Iuitl Wristbands - Better than Buremte Gloves for TP/WS when augmented properly, but again not much better.
Iuitl Tights - Same as Iuitl Vest.
Iuitl Gaiters - Same as Iuitl Vest.
Swapping the whole set probably gets you what, like +2% DPS after you spend millions (in real gil or opportunity cost gil) augmenting it? Then it'll last you two month of not having any reason to use those jobs? Nice, but I'll pass.