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.
A world where most people know a few cantrips and even non-magical people can help to cast spells. Which is just as well because the big spells can only be cast with the help of large numbers of people.Most large spells tend to protect borders and stop earthquakes as they can be done legally, but there are those willing to cast bad large spells s well.A major part of law enforcement in this world is preventing evil magic.