I learned to dive in a university course, not PADI affiliated, so we had more class time and pool time than any "retail" course would have. And a damned fine instructor, an ex-Navy frogman, from the time when that's what they were called. So my perspective may be skewed versus a "commercial" certification.
But when I started diving, with a club affiliated with another college which had a program through their local YMCA and PADI (PADI instructor & program, YMCA facility for pool) two of the members both made the error of only turning on their valves 1/4 turn. Not backing them off--but only turning them on 1/4 turn. Each swore that was what they were taught, so my opinion of PADI went down two notches. Then a year later a PADI instructor was giving a navigation talk to that same club and he kept talking about the "Loober line" on the compass. Hmmm....It ain't "loober" its "lubber" rhymes with "landlubber". An instructor who doesn't know compass parts...and expects that certified divers haven't learned how to use one either. OK, third strike.
The plethora of bite-sized additional courses that PADI kept pushing at that time (night diving, spear fishing, weekday diving in months with an "R"...) just kind of soured me to the whole organization. Night diving as a course? Really? We had to burn a while tank with black-out masks while running an obstacle course, bfd if you're diving at night with a flashlight. That's the same ten foot visibility you often get in the DAYtime in the northeast.(G) Spearfishing? Yeah, a Hawaiian sling is pointy stick, so what?
PADI was oriented toward bite sized pieces, which I can understand. And a perpetual system of bringing the customers back in for more purchases, instead of setting them up to be independent and well-trained divers from the start. I've always disagreed, strongly, with that philosophy. And with the fact that while some organizations insisted on "panic day" in the pool and flunking students who couldn't stand panic hazing "because they might drown", I agreed with the contrary opinion that they were more likely to drown IN THE OPEN WATER if you let them get that far without panic screening.
Another one of those members (YMCA/PADI trained also) had a regulator diaphragm leak at 75? feet in the ocean, made a panic ascent ignoring her buddy and octopus, and spent the night and next day at a chamber.
So while I wouldn't say the PADI philosophy has been "wrong" from the start...I do say that I vehemently disagree with their methods and I compare their success to McDonald's burgers: A mediocre excuse for a burger that any pub or diner can beat six ways from Sunday. But sold cheap and heavily advertised, and very successful with the public because of it. What they do, and how they do it, has made them huge. And if the Nooze keeps making a bid deal out of divers who die and the lawsuits their estates bring...PADI style "bite size" training could leave us with what the sport needs least of all: Government regulation.