Plagues and other great diseases are important parts of history and some settings. They defy man and may even defy God in their swift and terrible punishment upon the body of society.
My issue with modifying/removing dwarves and elves is that the PC’s may want to play them.
One of the most powerful tools found in the World Building 102b article is the Worksheet. Here is a place to put the settings you might make with them.
The massive blade known as Consequences carries several potent enchantments of battle, but also has a frustrating quirk: Its wielder finds himself unable to put it down until he enters the presence of a magistrate or other authority. Even then, it instantly returns to his hands if he has committed murder and fails to confess. Unless he somehow resists the blade's magic, the weilder's hands then run with fresh blood; the judgmental blade fights his every motion until he confesses his crimes.