Barleywine
Interesting perspective Barleywine:
Here is the deal from my perspective: The divine wants to communicate in a reading. However, the Divine never read all those fancy books or web sites on cartomancy, and doesn't know all those clever techniques. That is one reason as to why there tends to be so much error in many readings. People are trying to use techniques to provide all the details when the Divine wants the reader to get the big picture. Now, I realize that most readers will disagree with the approach of simplicity, and that is just fine. People do tend to like their rules and techniques. We all have to find our own way.
I respect that. I'm more of a Spinozan Pantheist myself. But certainly, before I use any of the more iterative techniques, I look for big-picture "signature" themes or motifs, what used to be called a "gestalt" approach when I was first learning how to synthesize an astrological chart. I just carried the concept over into tarot and now Lenormand. Something important will usually show up in more than one way. So for me, "simplicity" provides the vessel and more "granular" techniques fill it up with detail.
I find this a little harder to do with the GT, which often has "clusters" or "pockets" of localized significance depending on the various focus areas of interest to the querent. I also find it unrewarding with 3-card spreads because there are too many gaps in the narrative for my taste. But it works well with 9 cards.
But I was also an engineer for most of my career, and always look for an underlying (ideally organic) structure in any method of divination. I don't have much patience for more enigmatic methods that are impervious to scrutiny and "just work" without much of a conceptual framework. Hopefully, any such accretion of structure upon cartomancy was arrived at empirically, through experiential trial-and-error over a long period of time (like classical astrology in its infancy), and not just cooked up by every budding writer with a "better idea" and adopted by consensus of the less-informed or less-critical.
What has facinated me with the central focus card is the unlikely number of times that the Man or Woman card comes up randomly in that position when I'm doing a more general "current situation" reading for someone without a specific question. I figured there's around a 3% probability of that happening. The "trigger' card I'm less convinced of, but it seems to make sense as a "tone-setter" in the same way the second, "covering" card does in the tarot Celtic Cross. I see that some people use the first three cards in the GT for this purpose, but I don't at this point.