You hardly need ranking to find TCC schools that are simply in it for the money. You can find those without even looking, and almost none of them have a "ranking system". It would be detrimental to them to "rank" because then they'd actually have to learn their art instead of just peddling emptiness. I've attended a couple of this type of school myself, before I knew better.
I certainly don't begrudge anyone making a living, that's for sure. I hardly ever just go out and fix peoples computers for free, after all, I get paid when I do that. So if a skilled TCC teacher gets paid well for his abilities, I have no problem with that.
Now, when a person takes money to train others in TCC and they don't have the requisity skill to do so, then that's a problem. It hurts the art in general, not to mention the poor unknowing students.
So to that end, I see ranking as a good thing. As long as it's done by professionals who maintain the standards of their art, then ranking, especially when applied to those who wish to teach, seems to be the best idea yet. It allows an Association of this kind to be confident in the skills of their teachers, while at the same time allowing the teachers to feel more confident in their ability to teach.
If you have thoroughly tested those who wish to teach in your Associations name, and they have passed those tests, then you can feel at least semi-confident in their ability to correctly convey the principles of the art to their students because they have demonstrated their ability to understand those principles to your satisfaction.
By itself that is one very good reason to have "rank" in an Association like this. If your teachers are all "ranked", then you will almost certainly have a higher quality of teacher.
If, as you fear, the ranking itself turns into yet another way to pad the pockets of those at the top, then that too will pretty quickly get around and people will seek their instruction elsewhere.
Caveat Emptor applies in all professional endeavors, and certainly with bells on in TCC training, but if you've got a group of teachers who have shown their ablities by acquiring the proper level of "rank" in an established system overseen by professionals who have an interest in maintaining the quality of their art, then you've got a pretty good basis for stating that your Association has better qualified teachers than others and so people can feel much better about paying your teachers for their services in the expectation of receiving a good, high quality education in TCC.
Just another two cents on the subject.