Landstill is a blue-white control deck full of Counterspell, Mana Leak, and Prohibit, so Pyroblast is premium: it can counter their key blue spells (Counterspell, Mana Leak, Prohibit, Fact or Fiction) or destroy a blue permanent like Standstill or an animated Faerie Conclave. We're trimming Mogg Fanatic and Lava Dart since small pieces of removal are less important than disruption against a near-creatureless control deck. Flaring Pain stays in the sideboard: it only stops damage from being prevented, which does nothing against Swords to Plowshares' life gain, and Landstill's mainboard has no damage prevention for it to beat. Price of Progress stays in the main deck, because Landstill plays a large number of nonbasic lands (Flooded Strand, Adarkar Wastes, Mishra's Factory, Dust Bowl, Faerie Conclave, Coastal Tower) and the spell can deal a lot of damage to them. We keep our land count as is.