[Endoperez]

Banishment works against undead and demons, and nothing and no one else. That doesn't help your expansion except in rare cases.

Blessing is good, but ONLY if you invest some points on your pretender's magic and build sacred units. Sacred units aren't always your best troops and are almost always more expensive in at least gold than your other units, so this depends heavily on nation.

Luck is always good. Healing Light is a rarely-used spell, and making it an actually useful spell by making it holy is a great idea. While mages always have something better to do, you won't mind priests casting it.