We've had this suggested before, but the original reporter was happy with simply drag-and-dropping the particular folders he wanted imported into Shotwell, so he closed the ticket. Drag-and-dropping is also recursive, but it's easy to select a lot of folders with exactly what you want and drop them all in at once rather than one at a time with File -> Import From Folder... Does drag-and-drop solve your problem?
Michael,
We've had this suggested before, but the original reporter was happy with simply drag-and-dropping the particular folders he wanted imported into Shotwell, so he closed the ticket. Drag-and-dropping is also recursive, but it's easy to select a lot of folders with exactly what you want and drop them all in at once rather than one at a time with File -> Import From Folder... Does drag-and-drop solve your problem?