As I went through the first three laws (Reduce, Organize, Time), I realised that these arguably form the basis of what I think makes Artefact Cards work. Perhaps this what drew you to the Artefact Cards, subconsciously or otherwise?
You highlight the importance of that which may be lost in the design process; the peripheral stuff that falls by the wayside at an early stage, and doesn't return. By having everything out on the table, your eye can be caught by something at the other side, you get that 'aha' moment as you connect two things together. I don't feel digital does peripheral vision very well, not yet at any rate. Have you seen anything in the digital space that tries to address this?
Finally, it's 2014, and we still use a lot of paper, pens, sticky notes, Artefact Cards... can you see a time when other technologies replace these things.