I'm sure that this has been suggested but I'd like to see a markup that maintains a link to an original markup in the document (or in a separate PDF or database on the user's machine) and syncs with the content of that markup. In our work we run into lots of multiple source of truth mistakes. It's also a pretty major pain to make changes to toolsets or large numbers because they're all copies of each other.
I think a markup that maintains the exact properties of an original prototype would be great but even cooler would be if only certain fields could be dynamic references. For example, rectangular markup that represents a refrigerator in a floor plan with subject and label fields linked to another markup of the front elevation of the refrigerator, a different W, H, or scale than the plan drawing. Then if the spec for the refrigerator changes only one markup's subject field needs to be changed.
For those with CAD/BIM experience this would be like a Revit family, an AutoCAD block refeerence, or a SketchUp component definition.
