The Rock's Cabal Therapy and Duress attack your hand while Pernicious Deed threatens to wipe your board of Survival of the Fittest and Birds of Paradise, so extra Duress copies let you proactively take their Pernicious Deed or removal before it matters. Naturalize can destroy a resolved Pernicious Deed before they sacrifice it, protecting your engine pieces on the battlefield. Wall of Roots comes out in part because The Rock has Smother and Cabal Therapy ready to answer small creatures anyway, and you'd rather hold disruption. This is a measured swap that keeps your Birds of Paradise count intact for mana.