I too have taken DIRF (workshop) and lurked/helped during numerous classes since taught by several different instructors. Even during the workshop days - when the classes were really intended for pre cave/tech crowd - the instructors didn't give a flip if you were not actually planning to go Tech or Cave. OK, so having an open mind helped with that. Many of us Rec divers have dive buddies with polished Tech/Cave skills and just didn't want to look so painfully "PADI O/W" when diving with them :11: The attitude from the instructors was to do as well as you could, learn from others, and to develop a network of like-minded dive buddies. I think that open-minded attitude is partially why DIR-F expanded so quickly into the Rec arena.
With at least 2-3 instructors and several dive teams in classes, there was a LOT of information and plenty of examples on video. You really got to know people at all GUE levels w/in your geographic area.
Personally, I also like the "split bar" concept for future DIR-F. If you manage to pass the "tech" bar, then you know you have options to pursue triox, tech, &/or cave courses right away. If not, you know what to work on to get there or what to work on to evolve as a strong Rec diver. Maybe workshop only for Rec only, pass/fail for Tech/Cave aspirations??
I would have also liked the "split sessions" concept of attending the class/workshop one weekend, then - if so inclined - get the pass/provisionl/fail evaluations after X months of practice. This really only works easily if you and an instructor are within easy driving distance for weekend divesites for the evaluation sessions. Clearly, it would be best if you had sound Tech/Cave buddies to practice with you so you're not reverting to bad habits w/o feedback.
Our workshops were really demanding as the instructors crammed in a LOT of discussion on top of the typical 2 1/2 day schedule (Fri 6 - 11 pm, then 8 am to 10 pm Sat and Sun). We were mentally and physically spent - can't imagine trying to "pass" anything!!
Since my workshop, I've seen a couple of instructors extend the class to 3 full days and keep a 3:1 in-water student to instructor ratio plus a dedicated videographer for each team. Plenty of time for gearing up, meals, chatting with classmates and DIR "lurkers", and much less stress during the dives. Any longer could be too much time off work for that level of instruction - especially the Rec only divers. I'd think 4 full days would almost always need to be split across 2 weekends??? Again, having instructors within driving distance or not will likely gate how the longer classes will be accomplished.