The idea is to prevent line fill symbols like hatches from being rotated with the dataframe. For example, allowing a 45 degree hatch, to remain a 45 degree hatch, regardless of dataframe rotation. This would also resolve issues of dissimilarity between symbology in the legend and symbology on the map.
This could be added to the existing "Rotate marker symbols with dataframe" option that is available in the Advanced ArcMap Settings utility or as a separate option.
