This reminds me when they implemented ninja in FFXI, it wasn't SE idea to make NIN as a tank, but people found a way to replace PLD with NIN tanking, and then some encounters later on you would briefer a NIN instead of a PLD because they could avoid too much healing to a PLD, and PLD became useless.

Then they buffed the PLD Def to make him useful again.

No thanks; this will break the balance of the game.