Flood! Also, (and I doubt they'd ever do this, but...) it would be interesting if they implemented elemental resistances/weaknesses (ex: Flare and Flood add water resistance debuffs in FF Brave Exvius). That would add synergy for White/Black mages. Obviously it could create a balance nightmare, but elemental weaknesses have always been a part of FF, and it could introduce very interesting new fight mechanics. Perhaps if they did something similar for unaspected casters...