Why are there no standards ?
The simple answer would be because that is the way it is. But the truth is that most of these organizations are membership organizations and so they can't think globally.
Think Globally? Most of these organizations do not have missions to serve anyone but their members and grow their membership. They don't have missions to create standards.
The nature of New Thought is to be new! Thus the teachings of today will be different tommorrow. The classic texts are in New Thought Library. You can read them for free. But courses are continually changing and teachers are dying and being reborn.
You set the standards You set the standards by your excellence. You go to one of these institutes or schools or seminiaries and you be more, do more and thereby you can give more.
Ask yourself what the standard should be Should the standard be artificial and set up by a pariticular "commission" or existing denomination? Or should we look into the actions of our teachers and listen to what they teach and then make a decision as to whether they are really qualified.
The bottom line is this If you want academic credentials go to University of Melbourne or Oxford. If you want to become a Spiritual Leader decide if you are Buddhist, Taoist, Christian, New Thought or something else. Then go to a Divineity School for that particular path and begin your path to being a teacher, a spiritual leader, but don't fool yourself, your degree, your education in a spiritual institution would not and probably should not be accepted as a degree at a regular university. After all there is a point to separation of religion from government. Think about it! ASK questions, do RESEARCH, get ANSWERS then decide.