Black mage is not easy to get high numbers on. The rotation makes it seem like a very easy class, but it's not easy to be a top tier BLM. That being said, SMN does not need a 17% increase because that is bathit insane. It needs higher ST damage by upping the potency of Fester to quite a bit more and reduce to CD on enkindle. That's all that is needed in combination with the mana issue.