WU leans heavily on Force of Will, Daze, and Stifle to protect Tamiyo, Inquisitive Student and Quantum Riddler, so Disruptor Flute naming Force of Will or Daze makes their free interaction cost {3} more. Ensnaring Bridge can stop creatures like Phelia, Exuberant Shepherd (power 2), Snapcaster Mage, and Quantum Riddler from attacking once we are low on cards in hand. It does nothing against Tamiyo, which has 0 power, and it also limits our own Glaring Fleshraker, so we have to watch our hand size. Defense Grid stays in, because it makes their Stifle, Daze, and Force of Will cost {3} more on our turn. Expedition Map is the lowest-impact slot to free up. Pithing Needle only shuts off a single named source. Karakas taps only for {W}, which nothing in our deck uses, though it can bounce a legendary creature like Phelia or Tamiyo in a pinch. Focus on resolving Karn, the Great Creator to tutor these silver bullets repeatedly through their countermagic-heavy deck.