In ArcGIS it would be nice if the legend file worked like the ArcPlot LUT. That is if I have a GRID that has values 1- 10. I create a master legend file that contains all possible values (e.g. 1 -10). Now I use this master legend file on 20 other GRIDs; however, some of the GRIDs have values 1- 8. In summary I would like the single master legend file to reflect what is contained in the map. That is if I have values 1- 10 I would like the legend to be populated with values 1 -10. If I have values 1- 8 I would only like values 1 - 8 be populated in the legend.
This idea has been merged with Live Legend defined by features in page extent for Data Driven Pages.