After having recently taken the PADI Wreck course, I don't feel the course itself was inadequate, rather there should be minimum standards for students prior to enrollment.
A bit of background: I have about 75 dives and have done "wreck dives" before without penetration. For the past couple months I had been practicing with my wreck reel and gotten comfortable with my pony bottle, as well as bettering my buoyancy, frog kick, helicopter, and so on.
For the course we were lucky to do 4 dives on the same wreck. Day one: determine potential hazards and map the wreck - where would the best place be to penetrate? Day two: line skills taking turns reeling in/out and following. Dive four was also penetration dive. This is where the fit hit the shan. Naturally, I did the reel because my buddy had never used one prior to that day. We buddy up and with the instructor head straight for the selected hole. The wreck lying in the sand at about 65' allowed sufficient penetration if within the light zone (130' total). There were a number of breaks in the structure large enough to get out of should anything happen. I entered a small room and saw on the other side a large, open cargo area that we were familiar with that opened directly into open water. Since we were technically still in the light zone, I went through and once we got to the cargo hold I signaled that I was done and this would be a good stopping point. I noticed that after my buddy came through there was a serious silt cloud. To my surprise, instead of allowing anything to settle, he immediately turned to return. I debated not following him in but the instructor followed suit. I considered leaving the reel and swimming to the original opening, but went ahead and followed them in. Since I had to wind the line I was slower and in the small room left alone with zero visibility. I felt for a moment a deep fear - all the air in the world would do me no good if I couldn't leave this dark, blind maze. I considered dropping the reel and returning to the cargo hold, but luckily I didn't because I could have gotten seriously disoriented. I waited for things to settle but my instructor reappeared to make sure all was ok and I continued with the line. I was only about 10-15 feet from exiting the room and all was well. I was very upset because my buddy had serious buoyancy issues and only knew how to flutter kick going into this. Even with a very basic penetration like we did, I still felt jeopardized.
I learned a lot from this experience: only dive with qualified people. Don't dive beyond my limits - even basic things can go terribly wrong. I, too, need to work on kicks, perfecting buoyancy and line skills before attempting anything like this again. Silt comes up easily and I had never experienced zero viz nor the fear and danger that accompanies it.
All in all, it was a great class for me personally because it opened my eyes to a number of issues. I think things would have been much smoother had there been pre-reqs for students prior to class, as the class itself was conducted well.
Just my thoughts...
EDIT: I should qualify my thoughts that the course ONLY can prepare students for basic penetration, up to 130' total from surface and within light zone. Beyond this, more training is mandatory in my opinion.