"Drow are cool; we want to play them, but they are evil." -> Drow are no longer universally evil. "Demons and Devils are cool; we want to play them, but they are overpowered and evil." -> Tieflings are invented; they are far weaker and not universally evil. "Dragons are cool; we want to play them, but they are overpowered." -> Dragonborn are invented; they are far weaker.