I think what's coming through, to some extent here, is that there ARE people who would like to know more about gas management and deco theory, and have better skills, and they're frustrated because the only places they see to do this are technical classes . . . and they don't want to do technical diving.
I started to say that I think there would be a market for a good, meaty, solid class to teach divers these kinds of things, but as I started to write it, I thought, "You idiot, you KNOW there's a market for it . . . " because Fundies is an extremely successful program. Successful, I suspect, beyond the intent or expectations of the makers. The problem with Fundies is that the equipment requirements put a lot of people off; a similar class, with predictable quality, that didn't have restrictive equipment requirements, I think would sell like hotcakes.
That's dead on, I would take DIR-F except that I'll be dammed if I am going to buy a back plate, more wings, a doubles manifold, etc. I don't dive overhead or confined spaces except on hardhat surface supplied. So, if someone modified the DIR-F program (or stole the information) and offered a course called, say "Advanced SCUBA Thechniques and Breathing Gases" one would make a lot of extra duckets.
Disclaimer: Even though I play a SCUBA Instructor on TV I do not teach SCUBA.