I certainly agree with all the comments about procedural measures vs. designed-out measures - it's always preferable to design out the potential issue rather than mitigate it with procedural stuff.
And I see a pattern of generally poor design with these coaches, evident from all the non-safety critical problems with them.
One thing that seems strange to me is that it is necessary for anyone to get on the track at all (which inherently presents safety risks). I'd have thought that once you'd gone with Dellner couplers, then you'd try and make all the other stuff accessible from the platform side or the gangway end. Is there a particular reason that the ETS jumpers and the 61-way jumper could not be located higher up?
Maybe the answer is that the arrangement on the loco, where the Dellner has to be lifted into position, means that someone has to go onto the track to do that, and once that's a given, why bother trying to relocate the other stuff.
But the whole setup reeks of design compromise - the kind of thing where perhaps someone, at some point in the process, should have said, wait a minute, do we need to rethink this whole thing from the start? It's a familiar scenario to me, and one that often occurs when you have a lot of people involved in designing something, and also when it is being done in a rush. You start out with a basic concept that makes sense, and then when you work out the details you find that certain things don't actually work in line with the concept, and it gets compromised, eventually to the point where it just doesn't make sense any more. And at this point you should go back to the beginning and rethink the basic concept.
In this case I can see that the starting point was to use an automatic coupler to simplify operations. But the end result is, as far as I can see, no simplification to operations at all. I understand that this is because it was realised that the Dellner system could not cope with the large number of electrical connections needed. So was there a point at which the Dellner system could have been abandoned, and an alternative automatic coupling system used, one which could do all the electrical stuff too, which would avoid anyone having to go on the track and fiddle around in awkward positions? I don't know the answer to that, but I can imagine it's possible that there could have been a different system, but these realisations happened at a late stage in the process where people didn't want to delay things with a rethink.
@Bletchleyite is right - good design doesn't mean just following the specs in the brief but pointing out, at early stages, things that haven't been thought about, and suggesting changes to the spec if it allows an overall better design outcome.
Probably it isn't fair to blame things all on CAF - it appears that they were probably being briefed by an inexperienced 'customer' and that this must be part of the story.