Izzet Prowess is extremely fast and low to the ground, and Fatal Push fights their small creatures fine but you want more reliable, flexible interaction, so Consign to Memory comes in to counter their colorless spells and any triggered abilities they rely on. Mystical Dispute is strong versus their blue spells (Preordain, Expressive Iteration) for a single mana. Prismatic Ending is unreliable converging enough colors quickly to keep up with their tempo, so it comes out. Keep Solitude and Orcish Bowmasters, both excellent at answering their small threats and punishing their card-draw spells.