As a system of 16 behavior types it fails consistently to conclusively assign a single type to an individual. The slightest divergence from a profile will lead your halfway into another, the borders are unclear and could never be cleared up because...
there is no way to determine what each type acts like (to do so we'd need to know who is what type, circular reasoning anyone?)
As a system of 8 cognitive functions, organized along two sets of dichotomy [E&I] [T&F,S&N] which form types through preferential order, it doesn't work.
Even accepting the existence of the cognitive functions as named in MBTI, each function is so essential to cognition that the idea of preference is absurd.
No one is using any function more than anyone else, we are all necessarily using every function simultaneously at every time.
No one is more skilled in the use of a function than anyone else, functions are inherent to consciousness. Better at reasoning is not better at thinking.
A preferential ordering of functions can't describe the different personality types which exist obviously and necessarily (as much as the colour green exists) because there is no such thing as function preference.
K obviously this isn't perfectly said and I hope you guys tear me a new one
I may not believe I'm a Te dom but I still believe that I am a communal reasoner, so help me out here.