Azorius Tempo relies on Starfield Shepherd's warp, Momo's flying cost reduction, and Springleaf Drum's mana ability to go wide and fly over. Clarion Conqueror shuts off activated abilities from their artifacts and creatures (notably Springleaf Drum) while being a solid flying blocker against their air force. Esper Origins is too passive against their proactive flying plan, so it's cut for a card that directly disrupts their gameplan and holds the skies.