I feel like in-combat use should at least have a significant cast time or similar impediment to be more on par with the 8s cast and MP cost of having been used by a healer. The 3-minute cooldown, after all, is essentially split among all non-healer players capable of using the Phoenix Down. We don't need to make consumables, duly rotated, outright superior to actual resurrection spells.

Other than that, I'm all for it.