As to being confuse by various gear configuratons... My experience with new divers begins mostly the day after they finish class. The students from all the local shops often (at the encouragement of the LDS) begin their OW post-class diving with our dive club. So I see them from the PADI, SSI and NAUI shops, fresh out of class.
Do you think they are NOT going to have to deal with various gear configurations when they dive in the real world?
They get buddied up with someone and have no clue how their buddy's configuration works - because they've never seen an octopus, if they were trained using an AIR2, or never seen an AIR2, if they were trained on an octo. As to a long hose and bunged backup, when you show 'em that 7' of hose, they just stare at you.
Students (IMHO) need to be exposed to a verity of gear configurations to dive safely with other divers post-class. In the real world, the new OW student will usually have to dive with buddies with different gear, and by NOT exposing them to the different configurations in OW class, the instructor is not really training them to dive safely in the real world. I would think different gear configurations on the DMs would be encouraged - that is, if the instructor is motivated by giving good, safe, rounded education, rather than just pushing another student through.
Some instructors need to get out and dive more with us "just divers"- you know, the people who really go diving every week with the students you pump out. But most instructors just give 'em a card, send them on their way, hope they'll buy gear and trips from them, and then go on to the next class. In every weekly dive club we have BP/W's, Air2's, octos, ponies, and all sorts of verity. Students not exposed to diving with gear configurations outside the single one picked by the LDS are not really ready to dive in the real world. How can the instructor feel good about giving someone like this a C card??
I personally wish there was more standardization (I prefer BP/W, unified team, and will not do more than a recreational dive with those outside of that), but it isn't reality.
That's okay. Let the LDS keep giving them C cards, and we divers will continue to fill in as mentors post class (that's how I learned, too). Which includes exposing them to a verity of gear configurations.