Leaving aside the situation in Thailand for a moment, what makes a good teacher? I mean "good teacher" in the academic sense of the word (educator) and not the practical way we, as teachers, manage to fit in with our surroundings (employee)
The pie chart
To simplify the answer, I propose we measure the capability of teachers through a combination of three determining factors...
1 - Desire
2 - Experience
3 - Training
In other words... to be a "good teacher" you have to want it, you have to know it and you have to be able to relate it to others!
If this were a pie chart, how big would each piece of the pie be in your situation?
Desire: How much do you want to be in a classroom?
Experience: How well do you know your subject?
Training: How well can you relate what you know to your students?
Both sides of the fence
In Thailand, there is a very common cry among many committed farang teachers, that their lack of academic achievement cuts them off from opportunities which they feel they would excel at if given the chance. I tend to agree with them. There is a shortage of capable and willing teachers and in an ideal world, we'd be judged on our merits as well as bits of paper picked up in our past lives.
Conversely, there is a screaming wall of indignation from properly trained teachers. 'Real' teachers who can prove their worth by virtue of past academic exercises and achievements. And they too have a sound argument. Would you ask a hospital porter to take your tonsils out?
No matter which side of the fence you are on, the desire to teach is the only piece of the pie that we all start off with. When we judge other teachers based on their experience and/or training, the 'desire factor' rates up there as just as important. It's my opinion that you cannot be an effective educator unless you want to be an effective educator.
In a changing world.
In the past, education and training were revered. In my youth, it was a significant achievement to go to university and get a degree. These days, there are so many graduates, that the reverence for formal education has diminished. In fact, four years of study may be a handicap in today's world! Many employers can see past academic trophies when it comes to knowing what's good for their businesses.
Additionally, in the past, employees stuck with their jobs for a lot longer. That world is no more as people flit around the job market like humming birds in a spring garden!
Corporate culture club.
The institution of teaching is a career path that has a foundation cemented in education and training... except in Thailand. There is an egalitarian philosophy in The Land Of Smiles which leaves room for everyone. No matter what your personal pie chart looks like, if you're willing, you'll find work as a teacher. Flitting from job to job is allowed and usually expected, if not always welcome!
When you are looking for work in Thailand you must first know who you are and recognize honestly what you are offering to employers. Different employers have different work cultures. Knowing where and how you fit into any work environment is imperative.
The world worships youth and in that regard, Thailand is no different. Many schools, universities and businesses will happily train up inexperienced young people. They are cheap and malleable. Other employers have decided that a culture of experience will work better for them. There's no need to teach an old dog anything, right? Once again, it's a matter of how you fit into that working environment.
How delicious is your pie?
There is merit in education and training as much as there is value in experience and knowledge. The often mean-spirited superiority of one over the other has consumed message boards ever since I've been in Thailand.
For many commentators, there is no gray area: You shouldn't be in a classroom unless you have been trained to be there or you shouldn't be touting your training/education as validation of your teaching proficiency.
In reality, these extreme views are impractical. It's true that proper training will give you a headstart but no-one is left out in the cold... not in Thailand. The only asset we all start out with is a desire to teach... everything else comes later. When we're young, the value of our desire to teach is the most important piece of the pie. It alone determines our future education and our eventual experience.
Then again, perhaps (like me) you got your calling later in life. Experience is all I have!
When I lost my cherry to teaching, my pie was all desire. Nowadays it's about half desire and half experience. I've picked it up over time and now I'm good at it. I've also learned to have fun with the opinions of people who don't know me... and that's the custard on top!