Cursed Totem shuts down activated abilities from creatures, most notably Nantuko Shade's pump ability, denying it a way to grow out of range of your removal and blockers. Thwart is too slow against a deck full of efficient discard like Duress and Cabal Therapy that can strip it from your hand before you cast it. Powder Keg is also strong here, answering Nantuko Shade and Hypnotic Specter once you have the right counter count. Keep your counterspell suite up to protect key threats like Black Vise from their removal-light but discard-heavy disruption plan.