I say this as someone who is a Native-English speaker and also work in the very industry that I am talking about. I have worked as an English teacher in Thailand for going on 3 years and as far as ESL (English as a Second Language) is concerned, there is a massive emphasis placed on having native speakers take over the role of team leader in kids as young as kindergarten and even pre-school.
I can say, that even though this opinion directly impacts my ability to have a job over here that this is the wrong approach and I don't even understand how it got started.
In the years I have spent teaching ESL I have had mostly elementary school level students and our classrooms quite easily have descended into chaos. This has a lot do with the fact that the time the students spend with foreign teachers tends to not have any Thai oversight and it is very difficult to control children anyway, especially when you can't understand what they are saying (in both directions.) There are some stars in the classrooms, sure, but mostly the kids fall into a bracket of not really understanding what you are saying to them and I have only met a few foreign teachers that can speak Thai on a good enough level to communicate with Thai children.
I really feel as though the Thai teachers should be teaching English and the foreigners should only be put to work as assistants to "refine" the speaking capabilities.
There was one instance when I was working some part-time hours with a very ambitious Thai teacher who arranged private lessons on the weekends for students who (presumably at their parent's behest) were in for extra lessons a few hours on Saturday and Sunday.
When the Thai teacher (who obviously is fluent in Thai because she IS Thai) was explaining grammar, there were certain nuances of my own language that I didn't understand what she is talking about. I use grammar correctly just because of the fact that I have spoken this language my entire life, not because I actually think about the grammar syntax when I am writing it or speaking it.
When a Thai teacher is explaining these rules in Thai, it is far more effective in getting the language skills to "stick." There are many things that I and every other ESL teacher does correctly and almost certainly better than even Thai teachers with Master's Degrees in English, but we don't know WHY we do it that way, we just know that this is the way that it is. I hope this makes sense.
During these sessions I would serve as an advisor and would quiz the kids in spoken banter at the end to help them to REFINE their speaking and writing skills. These kids saw great improvement in just a few weeks that I don't think they would have achieved if I, or anyone else with a few years experience as a teacher were their sole instructor.
Also, and this is a big point, kids tend to be little assholes if they are not kept in check. I can say this with impunity because I actually was one of those kids that was constantly screwing around during class as a youngster. It was only be being reprimanded that I eventually started acting right.
This is extremely difficult to pull of when you and your students do not speak the same language. Thai teachers are absolutely exceptional at enforcing good behavior because there is a tremendous amount of reverence and respect that is demanded towards teachers in Thai culture. This same level of respect is not extended to the foreign teachers except for at the very expensive international schools that I am not qualified to work at.
Recently the Thai government declared that they were seeking an additional 10,000 foreign teachers to work as educators in Thailand and honestly, I think this is a huge mistake despite the fact that my livelihood depends on them continuing to have faith in foreign educators.
I feel as though foreign teachers should only be used when a student has already achieved an advanced level of proficiency and definitely NOT when they are just starting out. It simply doesn't work.
I mean no offense to anyone out there in the Asean community that has this sort of job but honestly, that is my opinion based an several years of experience.
On a side note there is a funny series that pokes fun about bad English education called "Learning English with Teacher Phensri" that is probably only funny if you have lived here and here is a clip.