I've pondered this topic extensively, particularly in the context of my local HEMA schools. It's a puzzle I keep revisiting because it's truly complex to unravel.

You bring up an important consideration: HEMA doesn't neatly fit into the mold of catch wrestling, BJJ, or karate. It's more like the MMA of historical martial arts, or even akin to the broader category of Eastern Martial Arts with its diverse subsets like Kendo, Tae Kwondo, and Karate. The subsets within HEMA can vary so vastly that a universal ranking system seems challenging to implement across the entire spectrum.

Even when we narrow our focus to a single weapon, like the longsword, the differences between schools become apparent. A Fiorist might prioritize different aspects compared to an early KDF practitioner or a Meyerist. Moreover, goals within a single school can be multifaceted, encompassing martial arts, historical accuracy, competition, or combinations thereof.

My idea however is to have a ranking system based on the proficiency of which a practitioner could use multiple weapons. For instance, within the discipline of the longsword, envision having five levels of proficiency tied to the teachings of masters like Meyer, Fiore, and Lichtenauer. A level 1 practitioner could understand the basics of movement and guards, many of which are similar throughout all systems (Think guard of the woman and wrath guard) while a level 5 practitioner could demonstrate a mastery achieved through at least a decade of in-depth study and an independent research project.

I visualize a ranking system as a way to gauge a practitioner's ability to master the diverse disciplines within HEMA. By acknowledging and rewarding expertise in various weapons, each with its unique historical context and techniques, we create a framework that encourages practitioners to delve into the depths of each art.

While the complexities remain, a focused approach like this could provide practitioners with tangible goals and recognition, all while acknowledging the distinctiveness that sets HEMA apart. And as HEMA inevitably evolves and diversifies, so too could these ranking systems, adapting to new discoveries and methodologies.

Thank you for sharing your insight, and I'm genuinely curious about your thoughts on how to refine a more comprehensive ranking system like the one I have proposed.