The BC was an evolution. First, it was used as a safety device and then I am sure someone found out that you could inflate it at depth to keep you off the bottom. Then power inflators and OPVs were added. However a horse collar would still float an unconscious diver face up on the surface. A stab jacket would do the same. A back-mounted wing would not. Now it seems people have back peddled and said surface flotation is not needed. A diver in a wetsuit is buoyant but the wetsuit is not guaranteed to float him face up.
I understand weighting and know that to be neutral at the end of the dive you have to be negative at the beginning. What if you have problems at the beginning of the dive? If you dive a balanced rig then you should be able to swim it up or at worst drop weight. However, how many divers have heard of balanced rigs? Probably a minority of divers. What if you get a major dry suit flood? What happens then? For the vast majority of divers a BC is a safety device.
As far as training goes I see no point having students swim laps with a tank on their back. Do you think they are going to keep doing that to maintain fitness? As far as training as a free diver first it would depend on how many skills transfer over. As far as I know the Army does not train helicopter pilots by first training them to fly fixed-wing aircraft. The Air Force uses trained pilots to fly their drones yet they have a worse safety record than the CIA that uses non-pilots. It would probably make more sense to spend the extra time evaluating the trim and weighting of individual students and teaching better kicking techniques.
I think you're taking too much of this out of context.
The point I try to make is there is way too much dependability placed on BC these days. With the size of some of these air cells and the way some or maybe most students are trained, the lift and ability to float an overweighted diver on the surface is taken to an extreme without the student ever knowing how dangerous that can be.
When I dive with or without a wing my surface condition (weighting, buoyancy) is the exact same. Where I dive with the suits I use I can float on the surface with no air in the wing (meaning also no wing) with a full tank. Many people can do this. I have attached the link to the Socal backpack divers group many times shwing many people doing this. This is how they used to do years ago and did all the same recreational dives we do these days. In fact, the first Doria dives were done by divers in wetsuits with no BC's and twinsets using double hose regulators.
One of them happened to be a woman BTW.
I'm not advocating that everybody dive with no BC, the point is if people can easily stay alive and floating on the surface with no BC then why are people dying on the surface with BC's?
I don't use a balanced rig, I don't believe in them. I don't use drysuits, I don't like them, therefore I will never have a catastrophic failure or a flood. I dive wet, and I make sure with whatever wetsuit I'm wearing that day that I am weighted properly and have a few lbs to dump, usually the amount of lift the suit will lose at the deepest depth I plan to go which isn't that deep these days. Total amount of weight used including plate tank etc. = being able to stop at 15' at the end of the dive with no air in the BC and hold the stop with breath control alone. Anybody can learn to do this if they want. To circle this all the way around from where we started, ...For me this means that I can float on the surface at the beginning of the dive with a full tank...
Regardless, I would never weight myself to the point where I would drop like a brick as soon as air is let out of my BC. I don't weight myself like that when I freedive and I don't when I scuba dive.
Being that I was a freediver prior to scuba diving, I learned to descend doing the pike and tip forward head first and swim down. That training carried over into my scubadiving and I do the same thing. I use many of the same techniques the difference being that I can breathe underwater, but all or most of my body hydrodynamics are very freediver-esque.
The swimming with a steel 72 on the back, yeah I know a guy who did that (true story). Don't be confused though or take it too literally, I didn't mean that should be something done these days, that was just an example of how tough they had it and how easy it is now in comparison. I would never expect somebody to be able to do that now.
Just like no BC diving and how it is now. Sometimes I like to point out history to bring to light how rediculous some things have become when they didn't even have some of those things in the past to cause such troubles. Sometimes things are invented to make life easier, but they cause bigger problems later. I think a BC is a good example.
I use a BC, but I also can go with out one. I know it's a luxury, what it's supposed to be used for, and what it
isn't supposed to be used for.