We typically follow the lead of the architect on the majority of our projects. We link in their Revit model at origin to origin so our coordinates match up. Some of our architects standards are to start all projects off at 0'-0" and set up a shared coordinate for 0'-0" to equal 100'-0". Some start all projects off at 100'-0" and if for some reason the contractor wants to see the datum elevations of 860'-0" they will move the project to Revit's project coordinates of 860'-0". We would follow their lead and try to avoid the entire project being moved after it has been started. In some cases the right choice was to set up a shared elevation in lieu of moving all of the elements in the model to a new position. Anyways, the GCS was not friendly in displaying the shared elevation base when it was required for us to take that route. We would either miss out on the opportunity to use the GCS, place text over top of the elevations and maintain their position, or place a note on the schedule saying 0'-0" = 100'=0".
After dealing with this for a few years I just got so use to the work-arounds and kept requesting that the architect not use a shared elevation base that I stopped looking for it to be added.
Enough rambling.... if you didn't notice this behavior change (like me), hopefully this post will brighten your day.