Ash

I don't understand why Quistis is even on this list. Her most powerful Blue Magic spell, Shockwave Pulsar, is one of the only abilities in the game that can break the damage cap. And if you use Aura (like you should), you can proc her Limit Break practically every turn.

If you have enough money, you can just buy the lockpicks from pretty much any blacksmith regardless of which point you're at in the game. The only difference is that blacksmiths toward the end have more lockpicks in their stock. There's also a Craftsmanship talent that uses extra pieces of material to automatically make lockpicks whenever you make something at the anvil.