Greetings..
"Closed door students", "disciples" or whatever method is used to determine who gets the "real stuff" is a bit like discrimination.. unless, of course, it is known up-front.. if new students are told of the hierarchy and the expectations to "get inside", then they can make an informed decision about their teacher's intentions.. I think it's dishonorable to take a student's money and not be sincere in the effort to teach them all they can absorb.. arbitrary exclusion from the "real stuff" should be clearly communicated to the hopeful student, and the reasons why as well.. As teachers, we are obligated to inform of flaws as well achievements, in that way the student can decide to make corrections or not, and when it's clear that they don't intend to meet the requirements to move ahead, we are obligated to terminate the relationship.. or, tell them they are welcome to continue contributing to the school but no advancement should be expected.. we are obligated to be honest with those that invest their time and money for our services..
As for grappling and Qinna, it is difficult not to see those elements in almost every posture, in almost every movement of Taiji.. if it isn't apparent to someone, they simply don't have "Martial Spirit".. similarly, it is also apparent that each movement and posture opens or affects meridians and gates.. Taiji is a work of genius, offering such diversified life enhancing opportunities for the those with the vision to see it..
Be well...
TaiChiBob.. "the teacher that is not also a student is neither"