Jonathan, what is learning a language?
Many in the field of biblical languages mix-up linguistics and learning a language. Linguistics asks why a certain language is the way it is. the way that one would teach linguistics is different from the way one would learn a language.
Also, a language is not a field of knowledge but a conduit for communicating knowledge. That makes a language something different from the knowledge being described in the article.
However, the field of Second Language Acquisition, which studies how people learn languages successfully and otherwise, has already moved down a path that is parallel to the thinking in the article. Efficient language learning is seen to be a reflection of "communicative language teaching", meaning that a person must use the language itself (not a different language or a metalinguistic model) in order to learn a language. That means (a) that a person must use Greek in order to learn Greek and (b) learning about Greek and how it works is different than learning Greek. the first point has an inherent 'catch 22': how does one use what one doesn't know or have? That 'catch 22' leads many adults to chase point 'b', often leading to frustration or rationalizations like "ancient Greek" is dead so restricted abilities in the learner are acceptable and replacable by extensive linguistic modeling (using 'modeling' in the sense of the article).
Bottom line, from the beginning students must receive comprehensible input in the target language (Koine Greek in the case of this list) and they must communicate in that language. Massively and relatively rapidly. To quote Stephen Krashen, an SLA researcher, "TPR Storytelling [techniques of Teaching Proficiency though Reading and storytelling (formerly Total Physical Response Storytelling)--RB] are much better than anything else out there." Ναι, as soon as students/teachers experience this, lights come on and a successful path becomes visible although it is long and in a different direction from current practice. Forty-fifty credits of TPRS will produce results that are not currently visible in our field but would allow BA students, for example, to listen to a Greek lecture on the development of the Greek novel. Notice the ironic full circle--listening to a lecture, something warned about in the article, but now an end part of the very communicative framework that interactive learning requires.