honestly, if i need to play defensive or need the atk down and ex slot (not in the case of this event now...), i tend to use jeanne myself (unless it's my wind team cause gaia/arc combo is too OP and would kill some potential damage output). she's not bad if you know you have to tank a hit you likely won't survive otherwise (and her regen/DA move is somewhat decent). not top priority, but she is a soul people should have just in case... honestly, gaia/arc combo shatters all difficulty with the thunder acc quests (and possibly the thunder catastrophe we have if your damage is still good enough). the game isn't exactly friendly towards healers (except sol) and won't be until acension is a thing, which is where tanks like jeanne shine
and since you like jeanne in a lot of stuff, i assume you've seen Hidan no Aria (Aria and Scarlet Ammo)... they have a version of her in there