Fatal Push struggles against Affinity's many artifact creatures with low mana values but also its ability to use free spells to dodge timing windows, and more importantly Consign to Memory directly counters their free spells cast off Mox Opal/affinity costs since Consign hits any colorless spell. Mystical Dispute can tax or stop Metallic Rebuke and other blue spells for one mana. Prismatic Ending is less reliable here converging colors fast enough against their explosive curve, so it comes out. Keep Orcish Bowmasters and Solitude, both strong against their low-toughness artifact creatures and go-wide plan.