Similar to how the ordering of variables can be changed per drag-and-drop in the Parallel Plot in Graph Builder (see below), I think it would be great if the ordering of categories of nominal/ordinal variables could be changed per drag-and-drop in Graph Builder Elements that support a categorical axis.
I find it happens a lot that the default alphabetical value ordering is not what one is looking for in a given case and one needs to change it.
After dragging-and-dropping the categories in the desired positions, on a right-click one should then be able to say "Save to Column Property -> Value Ordering", similar to how this works for axis settings that are saved as a Column Property.
Parallel Plot: Per drag-and-drop the positions of Sepal width and Petal length are changed: