In short, if you happen to have a gameplan you've heavily committed to in your deck that happens to have a lot of overlap with a certain card type, then you might consider Possibility StormPossibility Storm
Try powering up your strategies with the additional cards of the extra pack
Lulu, Stern Guardian, Rikku, Resourceful Guardian, and Wakka, Devoted Guardian are all Precon cards that are on the lower end of things financially
One use per turn is the most efficient way to obtain a high level of card quality and so the fact that you have to pay no mana to use Library is an advantage overall
Infiltration Lens, Rogue's Gloves, Mask of Memory, Avarice Amulet all are in here for same reasonKusari-Gama: This is our only psuedo Boardwipe in this deck.Banshee's Blade: This, Bloodforged Battle-Axe, Cranial Plating, are in here cause they ramp up damage