DandyDon:
Sure. It's just my personal opinion, in agreement with the Original Poster...
Newbies are more likely than the more experienced divers to bump into things, i.e. reefs & rocks, lines, ladders, etc. and will benefit from the extra protection with fewer scraps and cuts. The more experienced divers are less likely to incur an injury.
I don't really agree with the more experienced diver wearing shorties, but - that's up to them.
I dunno, Don, maybe they needed one of those pony tanks.
To the original post: Sounds like some good lessons learned. It is really cool that you managed to reduce them to words and post them for all to read and think about.
There are so many subtopics that one could go into from all that you brought up, but you did mention "water movement" several times: current, surge, wave action and more.
That is the first and greatest lesson to learn, most divers can not see this forest for the trees. You have made a monumental step in understanding what "advanced diving" is all about- as you noted... depth really has very little to do with it!
We learn to dive in pools and lakes as was posted earlier, trying to find similar diving is hard! Here you took numerous small leaps that, when added up, almost caused a bad situation.
Unmanned small boat, small dinghy, no support, current, wave action, shore exit, and on and on. Any one of these criteria alone is enough to stress. You don't mention if this resulted in a ships mutiny over the stress, but I have seen simuilar. After bad dives, quite often partners get into real spitting contests. Better to be glad you survived and then dissect the dive, decide what went wrong and how to remedy in the future.
Some of your conclusions are dead wrong. Do not assume that the way to deal with a current is to "just go with it". Currents vary and can be played much as a sailplane pilot or Eagle seems to hover behind and over mountain pinnacles.
Do not assume that simply floating off and waiting on the surface will bring the cavalry. I know of on three day wait for such results.
Your book certainly showed the depths of the Rhone. Yet- you were "surpirsed" by your depth. Hmmm. Do not assume that simply because your computer says you are okay, that this is the monitor system for your dive~ you yourself learned the fallacy of that problem. Ascending in a current from 85 feet is twitchy business. How'd you handle that 15' three minute safety stop. Really?
I think, because of that skill of understanding and critiquing alone, you will have no problems. Glad you lived through it.