Yes, I would agree that the general topical traits of dichotomies are more visible. But they are also more ambiguous to leading to a definitive type, and also (taking for first statement in the post), not every type takes the full breadth of each dichotomy that is present in both MBTI and Socionics, or that is Jungian. For example, when it comes to the E/I dichotomy, sure, there are some really extroverted characteristics that are easily observable. But how E is interpreted isn't paralleled in Socionics, as well as there isn't a gradation of dichotomies in Socionics like there is in MBTI (like how someone can be 60% E and 40% I). So if I showed you a TiSe who was E (I have an example of one in my life), how would you explain that? The qualities of E vs I are purely topical in Socionics because the IEs don't equate to either. This is the same with the J/P binary, the qualities that come along with the Jungian J/P dichotomy are spotty at best in Socionics types.
I honestly see this "more visible," ie easier, way of justifying the use of dichotomies enough to promote its awareness through the type's name is a cop out and takes away the only integrity these types have as statements on their own. Yes,
is harder to pin down on a person, but
leading does not mean the person has the qualities of E, N, and P, as the letters themselves are only representative of surface personality traits that do not have a causal relationship to IEs. This is where you're tripping up.
You're reliance on the roots of Socionics is a weak one, and honestly, it is where you constantly retreat to. Both MBTI and Socionics are NOT Jung's inventions, they are influenced and adapted from his findings. There isn't a strict observance of Jung's teachings and definitions, both MBTI and Socionics took the model of cognition he was starting and grew off of that. It's not Jung's hypothesis that is popular, it's MBTI. What Jung is more often cited for is his writings on archetypes, it's there you can be a little more fundamentalist. What you're saying is to replace the importance of IEs and substitute for what you believe are well established dichotomies. Really, I don't know why you don't prefer MBTI after they have been developing functions as an auxiliary mode of deepening their types.
I ask you this, why do you prefer Socionics over MBTI? Or, do you not prefer it and are just here to check it out? Because you are way too attached to your opinion on the usefulness of dichotomies, which is exactly how MBTI types, and what Socionics is not founded on.