Naturalize has real maindeck targets in their list: Sylvan Library, Mox Diamond and Seal of Cleansing are all artifacts or enchantments. It is also held for their sideboard Aura of Silence, which taxes our Survival of the Fittest and Sylvan Library and can sacrifice itself to destroy them. It's a reasonable include given how much of their deck it can hit. Ravenous Baloth is a strong top-end threat that can sacrifice itself in response to Swords to Plowshares to gain 4 life, and it gives us a life buffer against their Call of the Herd/Werebear beatdown plan. We trim Arrogant Wurm and Nantuko Vigilante since this matchup is more about efficient threats and land disruption (Wasteland, Rishadan Port) than big creatures, and we want to preserve our own Armageddon plan rather than diluting it.