I would suggest if you are looking for a yoga teacher that you do not look for any ‘certification’ but whether they have an Alliance standing. There are several levels of Alliance standards…. RYT just means registered on the alliance, and indicates no level of training or experience. 200, 300, or 500 indicate how many hundreds of hours of training that meets the standards of what a yoga teacher should know, and an E indicates a teacher with some thousands of hours of teaching experience.
If your population is mostly people who want to do an asana based fitness program based on yoga then getting that sort of training might suit your needs. If you want the benefits of the practice to include more than stretching and strengthening you need a teacher who is understands, practices, and can teach more than asana…. breathwork, meditation, internally directed tools of focus, … all of that is important. Here is a very short video (I shared this recently on my yoga facebook page, because I think it explains some of the NIH research findings in a very easily understood way) that gives a very simplified understanding of some of the complexity of the practice:
And I agree that hands on work is vital in yoga. If your prospective instructor is someone who has trained for years, and taught, and went by a different path than a standard Alliance style training, then this could be fine. Plenty of people have taken alternative paths and are fabulous teachers and might decide to do something like the NESTA because something else was not possible for various reasons. But I think you need to know that they really understand more than just how to get in and out of down dog and head stand, or replicate a series of postures.