Please, add [DebuggerDisplay()] attribute to the major struct & and classes like:
- Coordinate2D & Coordinate3D to see the actual value instead of "{ArcGIS.Core.Geometry.Coordinate2D}" and "{ArcGIS.Core.Geometry.Coordinate3D}". If it is empty, just print "Empty" otherwise the coordinates like "18.46; 46.18".
- MapPoint: same as above, with wkid, like "18.46; 46.18; 4326".
- Polyline & Polygon: use Length, Length & Area (if not empty).
- GeographicTransformationListEntry: every entry has its own name. This could be the natural DebuggerDisplay for it, like "Hungarian_1972_To_WGS_1984_2", or maybe "Hungarian_1972_To_WGS_1984_2; 4327 → 4326" (two wkids at the end).
- CoordinateSystemListEntry: same as above, just use the Name property.
- SpatialReference: the name would be more natural.
This will improve the development experience a lot.
