Mono Red Madness wants to race with cheap burn and Guttersnipe/Kessig Flamebreather triggers, so cheap interaction and incidental lifegain matter more than slow value plays. Tragic Slip is efficient, cheap removal for their 1/1s (Voldaren Epicure) even without morbid, and can also finish off Guttersnipe or Kessig Flamebreather's 1/3 body once morbid is active. Sylvok Lifestaff buys life against the burn plan when equipped to any creature that's likely to die anyway, which is constant in this deck. Sadistic Glee is too slow and doesn't affect the race, and Accursed Marauder is a low-impact body against a deck that doesn't mind sacrificing a small creature. Keep the low curve and sacrifice synergies intact since this is fundamentally a race you win by grinding value and gaining life.