Amulet Titan wants to chain cheap ramp spells like Arboreal Grazer and Amulet of Vigor into a fast Primeval Titan or Scapeshift kill, so Trinisphere is devastating, taxing every one and two-mana enabler up to three mana and badly disrupting their curve. We cut our own Blade of the Bloodchief since this matchup is about disrupting their engine rather than racing. Devourer of Destiny stays in, since its cast trigger can exile a green permanent like Primeval Titan.