Say that you start with a base image and then you make some change, and then you pull up the Brightness-Contrast dialog, play with the values a little, and then finally select "OK". Now, you can see in the undo history that you adjusted the Brightness-Contrast, but you cannot see what parameters were used. This becomes problematic if you want to go back to correct a step that happened prior to your adjustment to Brightness-Contrast but wish to use the same Brightness-Contrast settings without having to repeat that work, or if you want to use the same Brightness-Contrast settings in another image or set of images you will be editing.

The interface for this could be a right-click accessible properties dialog per action, or a tooltip per action.