UW Control leans on sweepers like Supreme Verdict and Temporary Lockdown plus countermagic like Dovin's Veto and No More Lies, so Aven Interrupter is premium: it exiles their Teferi, Hero of Dominaria or a sweeper as it's cast, and it can flash in to block The Wandering Emperor's Samurai tokens. Clarion Conqueror shuts off activated abilities, which stops the loyalty abilities of their planeswalkers like Teferi and The Wandering Emperor. It is also a 3-mana flying threat that is out of range of Temporary Lockdown. Archon of Emeria's one-spell-per-turn restriction rarely matters against a deck that seldom casts two spells in a turn, and both it and Thalia are fragile against their sweepers, so trim them for flying threats and flash disruption. Keep Skyclave Apparition in to answer The Wandering Emperor and other cheap permanents like Temporary Lockdown.