I think it would be beneficial to have the ability to reorder label classes in ArcGIS Pro. With the ability to have multi-symbol layer drawing in ArcGIS Pro, it's often not necessary to copy layers within a map, which is really nice. The one thing I find annoying though, is that I may end up with tons of label classes for a layer now (especially roads) since I want to define different features to label at different scales. It would be nice to have the ability to drag and drop label classes in order to organize them more efficiently.
In the example below, if I add a new 'Local' roads label class it will be placed at the very bottom of the classes for this layer. It would be nice to be able to drag and drop it with the rest of the 'Local' roads label classes.