I have Vanille's debuff & heal specialty equipment upgraded to the point that the next stone makes them into an ultimate weapon and I can tell you that I alternate between them depending on the enemy because it makes a whopping big difference. I don't know how far you have them leveled, but Vanille definitely does a notable difference with her healing/debuffing between those weapons. Hope is pretty even with her without the staff for curing, but with the staff I notice a difference immediately. Maybe you have other equipment boosting Hope up with things, or maybe you just have him powered up to a different point than I do.

EDIT: Does anyone know what Simurgh does, btw? Even the guide doesn't tell you. "A very special synthesis" or something along those lines. Interesting...