I would say that CAD users are looking for GIS to enable the export of spatially adjusted cross sections and profiles of Geo-Data. As we all know, CAD works in the XY coordinate system... GIS uses Lat/Long... and moving from the Lat/Long to a XY coordinate system is not easy!
Usually diagramming cross sections or profiles of the earth's surface required the export of Geo-Data to CAD... and then starts the laborious task of ensuring that all geo-referenced data is appropriately represented in CAD (a time consuming and laborious task!). In addition to running two different programs, it typically requires multiple passes at the data to adjust things to get it to look right... to get the scale right and even get the diagram to a size that is appropriate for labeling and symbolizing. Handing off or working with projects in this manner can be a real drain on your time . . . not to mention sanity!
But I'm currently using a great solution to this problem! It's called Crossview for ArcGIS. www.aprimesoftware.com
It allows you to natively create a cross section directly in ArcGIS yet gives users (CAD or GIS) the flexibility to finish (label, symbolize, etc.) in either GIS or CAD. If you are working with high-end and high-cost geology or hydrology consultants you can create 10s if not hundreds of draft slices of cross sections of your geo-data. Doing this on the fly with a consultant can save time and make the workflow [censored] with scientists. It's pretty slick... check it out. www.aprimesoftware.com