FTR there's one Esper that's actually definitely worth a damn, but not in a good way. Zodiark's super attack (which you can now activate at will) deals fixed 60k AoE damage and thus utterly wrecks some encounters. You can spam it since Mist Gauges are rechargeable with Elixirs, and items, summonings and super attacks all have no charge time. It's a pretty boring strat - and you better get used to seeing that (still unskippable?) cutscene a lot - but its effectiveness can't be denied. It's one simple way to get through the dreaded Pirates trial that's for sure...