OP here. Thank you to whomever so timely resurrected the thread. After having to reschedule from April, my wife and I finally did the Primer course this past weekend in High Springs, FL with Doug Mudry instructing. Our goal is simply to become more competent and confident divers. We are total recreational warm-water divers with no aspirations for caves, wreck penetration, or anything like that--at least for the foreseeable future.
Our intuition that we we needed Primer before Fundies was spot-on. We had never dived in a BP/W rig before, and I can't imagine anyone diving into Fundies in that state. I only wish we had had time to try different configurations (e.g., STA vs. STA-less, weight on cam bands vs. elsewhere, etc.), but there was so much to cover that we couldn't dwell on the equipment. We borrowed some gear for the course (thanks, Kate!) but plan to buy our own soon.
Contrary to at least one relatively recent thread in which someone proclaimed he had some kind of epiphany the first time he tried diving a BP/W, it was no cakewalk for us. Rather, it felt awkward. We both have good buoyancy control and stability in our traditional back-inflate BCs, but in the BP/Ws we felt a tendency to roll and pitch. Each of us experienced near-somersaults a few times in the beginning. (Interestingly, the only time I did NOT feel a tendency to pitch was when we were nearly fully inflated on the surface; so much for that myth.) Adding a seemingly tiny bit of air to the wing seemed to send us up more than desired, and dumping a seemingly tiny bit of course had the opposite effect. Honestly, we felt frustrated--like clumsy new OW divers all over again. Maybe a BP/W is to a traditional BC as a sports car is to a family sedan in that it is just more responsive to the diver/driver? It's great that it is so form-fitting and customized that it's almost just an extension of the diver's body, but that can be a double-edged sword. By the last dive (there are four dives in Primer), we felt we were doing lot better, but we still have a ways to go.
So now we feel we have some direction for the road on to Fundies. GUE has been de-mystified to us, and we're no longer intimidated by "DIR" (not that the term was used in class--it wasn't). There was no kool-aid involved. Fundies will no doubt be challenging, but at least we don't feel intimidated by nagging questions of whether GUE is some kind of cult or military-like training program. Primer is just what it should be: a way to ease into the system without any pressure. We had fun and learned quite a bit.
The next step is to buy some gear and dive, dive, dive in it until we feel completely comfortable and stable. We have observed and attempted the basic propulsion techniques and want to practice those. I'm sure there are plenty of YouTube videos to watch.
I highly recommend Primer to anyone who isn't confident they're ready for Fundies. In fact, I suppose it's possible to put information learned in Primer to good use and never even go on to Fundies. It's not a bad way for someone who lacks a mentor to have an instructor show them a few things that they've been itching to learn.