J & P, just there to provide order, or something more?

[Totenkindly]

Why is that a profound flaw rather than perhaps an inconvenient nomenclature? Users trained on the actual instrument know J/P point to the extraverted function, which is only the dominant for E's? It might be a trick for people to pick up but it isn't about the theory, only about understanding the code. I admit that socionics has a perhaps easier-to-understand method with j and p but...

I didn't see it as a flaw either; it's merely nomenclature, and easily understood once you have the information, and not an unreasonable choice by the system designers -- it serves a purpose.