The TL;DR Version
I am curious about the inclusion of the TLDR section at the end of the piece. It seems a stark deviation from assigning what Boyle himself would call too many course readings. The inclusion of a TLDR almost makes the strategies outlined in the piece unusable for reading the piece itself. I wonder why it was included.
But this is not the main reason. The other three programs try to achieve the connection or linking between different topics or cards (mainly) by assigning keywords. But this is not what Luhmann's approach recommended. While he did have a register of keywords, this was certainly not the most important way of interconnecting his slips. He linked them by direct references (Verweisungen). Any slip could refer directly to the physical and unchanging location of any other slip.
Niklas Luhmann's zettelkasten had three different forms of links.
Many note taking systems are relying on the older commonplace book taxonomies and neglect or forego both of the other two sorts of links. While the second can be safely subsumed as a custom, one-time version of the third, the third version is the sort of link which helps to create a lot of direct value within a note taking system as the generic links between broader topic heading names can be washed out over time as the system grows.
Was this last link type included in Konrad Gessner's version? If not, at what point in time did this more specific direct link evolve?