Eldrazi Tron is loaded with colorless artifacts and lands (Expedition Map, Talisman of Resilience), and Karn's static ability doesn't stop our Nature's Claim: it only shuts off activated abilities of artifacts we control, and Nature's Claim is an instant spell, not an artifact ability. Nature's Claim is excellent against Talisman of Resilience or Expedition Map to slow their ramp. Veil of Summer is close to dead since they're colorless/artifact-based and their only black spell is Dismember, which isn't worth keeping two copies in for. The extra Pact of Negation protects your combo from Dismember or Trinisphere disruption on a crucial turn. Keep Consign to Memory in since it directly answers their colorless spells like Ulamog, Devourer of Destiny, and Kozilek's Command, as well as the cast triggers on their big Eldrazi.