I know it’s possible to remove the outlines from enemies, NPCs, and interactive environment (like ore nodes) by turning off Postprocessing in the Graphics options.
I suggest adding an option to turn outlines off by itself. I like being fully immersed in the world, and the outlines are jarring. Turning off post-processing also turns off visual effects that enhance gameplay.
I can still see the names of people and creatures by mousing over them or by holding down the Control or Alt keys. Why not have an option to select “View outlines and name”, “View names only”, “Do not display names or outlines”.