WU is built around cheap cantrips and countermagic (Force of Will, Daze, Stifle, Consign to Memory) protecting Tamiyo and Phelia, so Fatal Push is efficient, cheap removal for Tamiyo before she flips or Phelia before she can blink something problematic. Sylvan Safekeeper is largely dead since WU doesn't attack our lands or threaten our permanents with the kind of removal Safekeeper dodges well, as Swords to Plowshares just exiles creatures regardless. We keep the rest of the maindeck intact since our proactive green creature plan and Thoughtseize-style disruption from Grist and hand attacks remain relevant against their tempo-control shell.