I didn't really read through the entire thread, admittedly, but felt compelled to respond.
I think that some instructor might not be familiar with back plate with wings, and might not support its use in their class. A diver might be overweighted with a SS backplate and a weight belt, and it might be difficult to perform the required skills with such a rig. The skills in question include removal and replacement of weight belt on the surface and in water, and removal and replacement of BCD on the surface and in the water.
A pool dive with an 8 lb ss back plate, plus a required weight belt, plus a crotch strap ... Might be an ordeal for a new diver to accomplish. I find these set up, if securely adjusted, difficult to remove and don under and above water. Second, the exercise of removing and donning the weight belt might be difficult.
If the instructor is not familiar with the rig, and the student is not familiar with the rig, and the student struggled, who is going to help him/her? Now, if the student was wearing a heavy rig, and little weight on his weight belt, the gear removal might be a little dangerous with a wetsuit on. He might not be able to hang on, and let go of the reg and rig, and you might have an emboli occurring.
I can imagine that a lightweight bp/w rig with enough weight on a weight belt would be acceptable in an OW class... But one has to advice the student of the need to have good dexterity to put on and remove such a BC, and perhaps he should have it adjusted quite loose for such an exercise (at first).
You bring up some valid points - some instructors have not the faintest clue about BP/Ws. But whose fault is that? I would certainly hope that by the time you've reached the instructor level, you'd have the motivation and forethought to take some initiative and figure out how a BP/W functions, with or without help. In all honesty, if an instructor is too much of a tight-ass to learn about them, or whatever the reason, perhaps a better hobby for that instructor would be coloring with crayons (in between the lines please!!).
Setting up a BP/W and adjusting for correct weighting obviously needs to be taught, I COMPLETELY agree with you. I for one am surprised it's not taught in the padi curriculum (but at the same time, I really am not surprised). Nobody is so stupid that they can't understand it - so whats the problem here, really? I think it has more to do with money than it does anything else.
The dive shop I am a DMC at has instituted a policy of encouraging divers to consider a BP/W setup, even for first-time divers - which I was surprised to hear.
BP/W BCDs are superior to the vest style in so many ways and once you recognize all the advantages it becomes very hard to justify selling vest style BCDs to ANYONE with rare exceptions.
I for one, used to avoid hanging out on the shop floor at a specific shop because suggesting to customers, especially OW customers, that a BP/W serves as an excellent platform for ones diving - recreational or otherwise, always led to problems.
I've had other divemasters, and even instructors interrupt my advice giving/sales with customers on the shop floor, mid sentence, to "correct" me about the validity of BP/W for recreational diving.
BP/W are not scary looking - but they look uncomfortable, when in fact, they are often more comfortable than some "recreational" vests. I really see that as being the only major problem to over-come from a sales point of view. And it's a fairly trivial problem at that.
What it comes down to is some LDS' being afraid of change, and PADI and other major players hand holding and babysitting these same shops.
"awww, it's okay lds, BP/Ws are scary and dangerous. There there. sell these generic vest style BCDs instead. no tears. no tears"
