Against Sligh's low curve of burn and small creatures, we want cheap, efficient removal rather than discard that trades down on tempo. Vendetta kills Ball Lightning, Grim Lavamancer, or Jackal Pup outright, and the extra Diabolic Edict is a clean answer when they're down to one key threat. Graveborn Muse's life loss is too risky racing a burn deck, so it comes out; Smother and Withered Wretch (hitting Grim Lavamancer's graveyard fuel) remain important pieces of our plan.