I would like to see the ability to use Abstract feature classes in ArcGIS Diagrammer, similar to how they are used in Visio geodatabase design. I have one model that has about 24 feature classes and 24 related tables. Many of the fields across these layers have to have the same name and properties. So if one needs to be changed, it can be very time consuming to change them all, and it leads to a lot of chances to miss one little property somewhere.
