Great thread. Two points here.
1. At small clubs even having a restricted FI can be a major problem in administration. I personally like to have an FI(R) on the books as I enjoy the freshness they bring, BUT...my workload increases dramatically: having to come in on days off, check flights, taking them up in poor wx, etc. On top of that is the difficulty of explaining the FI(R) system to students, taking them for their first solos, etc. As I said, at a small club making that all work can be a nightmare. Imagine how difficult things would be if you had instructors that could only teach NPPLs. The situation would be ludicrous: a plane available, a PPL student available, good wx but only an NPPL instructor available, so no lesson. Even if the regs changed, I can't see myself employing, in effect, a seriously restricted NPPL instructor. Why wouldn't I continue with PPL instructors so that I had the flexibility to allocate them to any student? What's more, I think a split in the NPPL/PPL instructor system would worsen instructor salaries as a whole. Less instructor flexibility means more instructors would be needed to cover the same student base. An increase in instructor numbers with no increase in club revenue can only mean reduced pay for instructors.
So logistically and financially I think two instructor types would be a bad idea.
2. I totally agree that the ATPL written exams are entirely unsuited to PPL instruction. And given that the exams are called 'commercial' I don't recall a single subject being devoted to the pilot's role in making the organisation 'commercial'. Even my IR instructor tried to persuade me that piston engines were more efficient the lower you were! Subjects that are key to the commercial operation of GA just weren't covered: selecting the most appropriate heights to benefit from/avoid the winds, leaning off with no fuel flow or EGT gauge, dead reckoning in IMC to go direct route instead of beacon bashing; the list is endless. Still at least I remember that those stupid haboobs come out in the Summer.
Exactly the same inappropriateness applies to student learning methods. Basic psychology or education theory should be part of the ATPLs. Surely the ability to adapt instructional style, to recognise resistance to instruction, to learn to confront constructively, to understand different learning styles, etc, etc, etc should be part of our theoretical training. I know these can be covered in the FIC course but not in the same systematic fashion as ground exams. I thought the commercial written exams were supposed to equip pilots with the skills for all aspects of commercial flying, and yet they are so clearly designed for airline work and that alone. If the CAA treated flight instruction as an equal with airline flying and set the syllabus accordingly then these discussions about different instructor types wouldn't be needed - you'd need a pro to teach and that would be the end of it. That pro wouldn't need an IR or an MCC, so they could be a decent PPL, but they'd know about teaching theory. And if you think that this is only useful for PPL instructors, what about all those frozen ATPL's who eventually become TRI's. Commerciality and instructional behaviours should be an integral part of a pilot's training.
Therefore, I think there should be no change in the current system for instructors, but I would like to see the content of the theoretical exams changed.
Sorry for the rant, folks, a bad day I guess. Anyway, a very interesting thread.