There are elements of today's courses that I don't recall being included in my original YMCA class in 1972, and elements of that course that are considered technical diving topics or advanced skills today. For example, I think people were expected to know how to use a compass and pay enough attention to how to navigate underwater, so it was not taught. But classroom work included planning repetitive decompression dives using Navy tables, and open water tests included underwater doff and don.
But the biggest difference to me, by far, is that back then certification was binary. You were a certified diver, or you were not. There were no courses after the first. The implications of this might not be obvious. We were expected to be fully independent divers, to be able to plan and execute our own dives (which emphatically did include gas planning), and to take full responsibility for the outcomes, once the ink was dry on the C-card. Today's recreational training seems to have de-emphasized this aspect of things. But in today's world, recreational charters with pre-planned dives at known sites seem to make that OK.
Edit: If time allows, I'd be happy to take your online course and comment, but I'm afraid I won't travel to NC to do that!