4c Legends plays a wide array of resilient legendary creatures across many colors, so Day of Judgment is a strong reset against their board presence since they can't easily out-value a full sweep with so many singleton threats. Flashfreeze covers their red or green spells, countering green creature threats like Absorbing Man and Honest Rutstein as well as spells like Celestial Reunion, as it counters any red or green spell regardless of card type. Iroh's Demonstration's sweeper mode only deals 1 damage to their 2+ toughness legends, and It'll Quench Ya! is too passive against a deck this proactive, so both are cut for the sweeper and matchup-relevant counters.