eh, not sure I agree. Brannock is 2 dimensional only while some lasts (or certainly shoes) take into account at least 3 dimensions (or the 3rd dimension at different points)
I just know this from being misfit on ski boots for years and years until somebody finally figured out that I my foot was thicker than normal at a couple points
I agree with you that shoe fitting is not limited to two dimensions, but as a starting point using a reference that is arbitrary makes it hard to gauge.
We should start with Brannock and go with more specificity from there.