Here is how Lightroom does it.
Notice how the selected history action (left panel) is cumulatively reflected in the "After" image (right side of right panel).
In the upper snapshot, an action in the middle of the sequence has been selected. Note the appearance of the "After" image.
In the bottom view, the final
action of the sequence has been selected. Note the appearance of the "After" image.
The user can select any step in the sequence and view the cumulative adjustment at that point in the "After" image, just as described above for the MP Batch dialog.
Also notice the various options for the before and after comparisons beneath the Before/After images.
It seems to me this approach for building batch scripts could just as easily be applied to ad hoc image adjustment in XnView MP... with the result being BOTH an adjusted image (if desired) AND a savable script (if desired).
A "merged" tool set, if you will.
It is not too hard to take the next logical step and realize that different scripts = different versions (if the original image is preserved untouched)...