But I cannot think of a single scenario on any mixed gas dive to some wreck below 200' where the correct response to to "remove my set of steel doubles".
Separted from team mate, or in a tight space and tanged in something, net, wire, caveline, fishing leader, etc. Not that far fetched in my experience around wrecks in the N.E.
Your first point about good divers being able to make standard gear fit into different environments is well taken. But there are some distinctions between environments which clearly suggest that certain skills (such as doffing and donning a rig) are specific to different environments. (Yes, there are no doubt divers who would argue that they can remove and replace a set of steel doubles configured as you described, but this is by no means the norm and, depending on circumstances, may not be the optimal response.)
Agreed, but in some circumstances it will be the optimal response. I think it shortsighted to eliminate any possibility of that response.
Optimal equipment selection is often driven by considering the requirements of specific environments. I dive the wrecks off NC configured just like you are - rig has all the weight, I'm positive. And "re-thinking one's approach" is never a bad thing. But unless you intend to move to a recreational configuration that would more easily support doffing and donning your rig, I suspect you'll conclude as I did that doffing a set of steel doubles at depth is asking for grief; and in nearly any case you can think of, having a buddy next to you to untangle you is likely a safer option during deep mixed gas dives.
Having a buddy next to you is a safer option for all dives, no matter what your configuration is, no disagreement there, but things do happen.
I've had the chance to examine, in detail, over 2000 diving fatality cases and there's one thing that blasts through all the confusion and clutter:
rarely does a diving fatality stem from a single cause, it's almost always the result of a multiple series of cascading failures. And there's one really important lesson that I've learned that I credit with having saved my bacon a few times:
the effective ability to deal with any one of the items will stop the chain reaction. Being able to remove and replace ones rig is just one of those items, not some end all/be all that defines you as a "good diver" or a "bad diver."
We all evaluate what we need for personal and team safety and then we and our team live and dive by those choices. We choose to be diver neutral/rig neutral, it is one of our core values, it costs us nothing, it does not obviate a DIR style balanced rig, and with the proper selection of belt (or harness if you'd rather) it does not create any risk. I can not, for the life of me, see why anyone would do otherwise.
The entire objection to being diver neutral/rig neutral seems to stem from the very reasonable rejection (a rejection that we made almost 50 years ago) of an unsafe type of weight belt buckle without any consideration of the rather simple alternatives available. Get a rubber belt and try it, you may be surprised, and the life you save might be your own, might be your team mates'. Or it might never be an issue, but, if nothing else, it will help your trim.
