WBR plays a lot of resilient midrange threats like Cecil, Dark Knight and Bloodghast, so Obliterating Bolt's exile clause matters against anything with recursion or that would otherwise return. Cut Propulsion turns their own big attackers like Casey Jones or Carnage into self-removal, dealing damage equal to their power back at them. Sear is cut since 4 damage often just trades evenly with their bigger bodies where Obliterating Bolt permanently answers them, and Opera Love Song's card advantage matters less in a race where you need clean answers to their threats. Keep the aggressive curve intact since this is still a race you can win on the play.