Well if the bard does not have to Mage Ballad, he can use it on Foe's requiem instead, increasing damage for our mages, and will not reduce his own damage.
And it's more of a personal improvement I wish to attain to better manage my mana resources, rather than a "I cant beat turn X help!!" problem.

1 thing Zezeba pointed out that I'll take note is, reading the bosses' moves, currently I just follow a strict healing rotation, cure I + proc cure II for easy moments, cure I + cure II for oh shit moments, and cure I +Cure II x2 for OH MY GOD moments. But if I can read the enemies attacks, (example, know when a rotor swipe from dreadnought is coming), can precast the appropriate spell ahead of time, but I guess that may take lots off practice + attention .