I think I’m with richardg on this one. I understand your viewpoint in an academic setting if results on paper are important. In the real world (IME) my foreign friends fall into two groups - those who are willing to work out what I’m trying to say and run with it, and those (a very small minority) who find it tricky to understand what I’m trying to say if I stay beyond sensible grammar or pronunciation boundaries (frequent) and feel the need to correct me. Guess who I prefer spending time with, and with whom more interesting conversations take place? I like to think I’m in the first group myself when it comes to them trying to converse in English.
My dear Marchbanks, E.F.L. teaching covers a large area of different demands, environments, methods and goals. I taught in a large, very well structured school which had monthly modules, exams, business English etc. over 8 different levels from beginner to Cambridge Advanced and Proficiency. I taught at all ages and at all levels except beginners, but mainly intermediate and above and esp. the exam and advanced classes. We were frequently inspected within the class setting. Each level and class had their allocated text book(s) for class and homework use.
I was also British Council inspector for my school, travelling throughout Britain and Eire vetting and photographing accommodation, verifying the teachers' credentials and writing reports for the office; this occurred over a number of years from 1997; this was in conjunction with my normal teaching. I also did one-to-one concentrated teaching, but always preferred the cut and thrust of the classroom.
Richard, as many other E.F.L. teachers, esp. abroad, may well have not taught in this highly disciplined environment. In the 60s, I taught privately in Milano, and it was mainly conversational and I was ill-equipped to do much else but this still came under the general heading of E.F.L.
Believe me, those foreign students paying considerable sums after uni. or seconded from their job or whatever wanted the grammatical detail in order to not only equate to their own (European) language but also to explain why such and such is used. Explaining prepositional use and that of the present perfect tense are two salient examples here. They wanted to know 'why'; the teacher's job was to explain this usage, which would often differ from their own.
I may be old and grey now, and losing some of that acquired knowledge, but still hold on to that belief in the importance of the structure of our global language. There's a lot more to teaching than structure, of course, but this latter rather depends upon the creative abilities of the teacher, Grammatical structure does not depend upon variables (with the odd exception!). Maybe you can see where I'm coming from, to use an American (?) idiomatic term.