The 7th most voted Revit Idea is Non-Rectangular Scope Boxes. Unfortunately it's marked as a 'Future Consideration' because of the complexity to implement. I can understand this, since scope boxes are three-dimensional.
However, I don't see why you can't implement the next-best thing: matching crops from view to view. I'm thinking of a function similar to Propagate Extents for grids, except use it for crops. If you have a crop set up for one view, why not be able to click it, click a Propagate button, and select all the views that you want the crop to apply to?
This should work for both the crop and the annotation crop.
This would be much faster than copying-pasting the crop boundary from crop sketch to crop sketch...