That makes sense, and I'm not sure that debating something strictly dialectically is even possible as it would require keeping track of insane amount of data only to arrive at the realization that an axiomatic divide is often a matter of qualia. For the same reason, even the most honest dialectician has some casuistry in him.
This is incidentally what angers me when dealing with hardcore MBTI fanboys. It's like the answer to any criticism is "you don't understand the functions", as if their definitions weren't inherently vague. Over the years I tested as ISFP, INFP, ISTJ, INTP, INTJ and possibly INFJ, and here's the thing - I was able to perfectly justify it every time. The core issue is epistemic in nature; it's not enough to know the functions, you also have to know how to interpret your own cognitive processes to map those functions onto you correctly. Given that we don't exist in vacuum, I'm sure you can see why that's a bit problematic to say the least. Most explanations then amount to little more than ad hoc mental gymnastics.
Just to finish my thought about the Fi/Ti duality - Ti is often referred to as logic (or even "subjective" logic in contrast to Te "objective" logic - where the hell do people get this stuff? Red logic is blue logic is green logic.) and Fi as adherence to morality or self-understanding. But this distinction is arbitrary, because any sort of understanding or morality must have a logical latticework to explain why is it/should be so, regardless of whether that morality is meticulously constructed by you or enculturated (as Fe is often portrayed). This would indicate that in the case of IxFPs, they would have basically no idea why they act the way they do with Ti being last. Socionics manage to reconcile this by assigning different proficiencies across the stack, but then the ordering of the stack becomes unintuitive. The only noticeable difference seems to be in the fact that Ti is concerned with impersonal concepts and Fi with personal ones, but both demand logical consistency.
This may be partly due to my own ignorance, but at this point there are so many spins on the interconnectivity of the functions that it seems like an afterthought. Whoever keeps spreading these definitions should be soundly flogged.