Personally, I don't think much of the blog post. Until the government establishes some kind of minimum qualification for teachers of English as a Second Language, you're probably not going to see much of an improvement.
This is actually something I've always wondered about, to be honest. When I taught in the Czech Republic in 1999, Teachers of English as a Second Language were required to have completed a TEFL/TESL course (minimum 40 hours, though most schools wouldn't hire you if you had less than 100) to get a visa. We were told that this requirement was an EU requirement. If it is, it doesn't seem to be one that people in Spain use. As many of you know, language teaching is controlled by the Ministry of Consumer Affairs, and not the Ministry of Education. (That gives a whole new meaning to the expression "you get what you pay for". Or "buyer beware.")
Can anyone confirm if the requirements have changed? In the nearly twelve years I've spent here, I have never heard of a government requirement for private language teaching.