I was talking about immunity to instant/near-instant death (Doom and Tail Screw), percentage based dmg (Missile), stone and paralysis because they are just to strong (or just silly) against bosses. So the magic vulnurability, dmg reduction, blind, slow, heavy, silence and stun which the Blu offers are still there, unless the bosses aren't already immune to them.
Also I said that only bosses should have those immunities, not the trash mobs in dungeons or the open field mobs. Also, most bosses in most FF are immune against said status ailments/dmg types.
Or to make it short: I fail to see how the only thing making Blu unique is instant killing a boss with doom.
Thing is, for Blue Mage as tank is The Look and/or Mighty Guard absolutly mandatory. If your Blue Mage tank has no enmity generating skills, then he's basically useless. Therefor you have to make absolutly sure that he has at least The Look before running into the first dungeon.
