Hi Kirk,
My $.02.
In my experience, which is mostly in the news industry, by far the most popular sort order for DAM results is by time of commitment to the DAM (in this case catalog), with the newest items on top. So much so that users mostly forgot there were alternatives.
You would have thought it would have been by time of creation, but that option wasn't popular at all for whatever reason.
Pre-DAM in the workflow, in Photo Mechanic, was an entirely different story, with filename being the top choice, followed probably by time of creation, with newest in the bottom.
This might help when you decide how to present the sort order menu and whether it should be consistent between search and folder tabs...
-Carl