I just hope this won't end with hypocrite systems.

Like no bikinis supported, but you can use the level 40ish bikini platemail for vanity. Or Cloth can not be made into Plate, but Plate can be made into Cloth (which is the direct result if you can mix and match anything you can WEAR on a class).

In any case I really hope they allow bikinis since it was something everyone got their hands on cheaply. If they force us to use alternative items, I can see the bikini and shawl set being grinded by half the community and the queue being 5 hours to enter. (And the items on the AH being 500 000 gil each). It is NOT a good idea to create a choke point for the vanity people want.