The Japanese Language Textbooks for beginners

My former colleague asked me about the Japanese Textbook for beginners. Then I wrote this for her. This article is totally my personal opinion. I do not care if other Japanese instructors do not agree me.

I would like to recommend the best Japanese textbook for you, however I cannot find one, unfortunately. In my opinion, the method of the Japanese language education for foreigners has not been established perfectly.
We native Japanese learn Japanese as the national language (Kokugo) in the school, but foreigners learn Japanese as "Japanese." This means the Japanese language is little bit different from Kokugo, like English and ESL. ESL educational system and Language Development Education is already established in the U.S.. But the Japanese language educational system for foreign learners has not been developed completely, I think.
One of the reasons is the conflict between the researchers belong to Kokugo societies and other researchers belong to Japanese education societies. For example, the grammar terms using in Kokugo educational system are different from Japanese grammar terms. So the Japanese language textbooks are so hard to be used by Kokugo teachers. And, Kokugo textbooks should be examined by the ministry of education, science and sports of Japanese government, however the Japanese textbooks for foreigners do not need to have any check before publishing by national authorities. I cannot believe that Japanese government has no interesting in the Japanese textbooks for foreigners. That's why Japanese textbooks have many simple errors and mistakes are found by Kokugo teachers and capable Japanese instructors. Another problem. Some of Japanese teachers cannot realize the errors and mistakes in the textbooks. To earn the teaching credential of Japanese language education (not Kokugo), they just have to study the theory and grammar (of Japanese education, not Kokugo education.) They do not learn pedagogy, psychology and other studies related with education that Kokugo teachers have to learn. Additionally, most of them simply believe that the Japanese language textbooks are perfect, because the famous Japanese educators wrote them. But, in my opinion, they have to return the Kokugo textbooks. If they want to be "real" language instructors, at least, they need to have ability to find very simple errors and mistakes in the Japanese textbooks and claim the irresponsible edits to the publishers.