While I don't necessarily think there would be a problem with adding more...Only useful to WHM, PLD, and BRD? Where did you get that idea?

Army's Paeon is very useful for Monks because of Fracture (I assume this also holds true for drg skills?), and wouldn't it also be useful for WAR? not just PLD?

Foe Requiem can be very useful for BLM damage, especially their limit break.... I am not sure how good it is for SMN though I would imagine it would be useful for them as well.