Esper Blink is a grindy value deck full of ETB creatures (Flickerwisp, Phelia, Overlord of the Balemurk) and Thoughtseize disruption, so High Noon slows their ability to chain multiple spells and blink triggers per turn. A second Wrath of the Skies gives you another sweeper against their go-wide token/creature plan. Day's Undoing is symmetrically bad since it refuels a deck that is already grinding card advantage with Ephemerate and Quantum Riddler, so it comes out. Keep Teferi, Time Raveler and Narset in as they're excellent at shutting off their value engine and extra draws.