Selective Ingest has been on your list for some years now, and I'm still hoping it will be implemented. For me, here's why it would be useful:
I rename images on ingest according to location and date, as "Boston{datesort}_{seqn}." I recently spent two days photographing in Boston and Cambridge, MA. Each evening I had a card full of images from both places. I wanted to select and ingest all the Boston images, renaming them and adding appropriate other metadata, and then select and ingest the Cambridge images, applying the file names and metadata for Cambridge.
Using Image Capture, Lightroom, or Aperture, I could select just the images I want to import. With Photo Mechanic I need to use workarounds that add extra steps, slowing and complicating the workflow.