I am not advocating that boats that exhibit extremes in seaworthiness should be sought just that awareness of the compromises be acknowledged.sigh . . . I dont really want to engage in a debate about 'general' answers to the desirable/undesirable/seaworthy question . . .because it is damn complicated and there is no one answer, they 'all depend' on compromises one wants to make.
But, let me just point out that the design space is rather not generally moving toward narrow/heavy/full keel/barn door rudders - it is rather moving in exact the opposite direction (wider beams, lighter, fin-er keels and spade-er rudders). And that is NOT because the clients and their NA's are complete morons, but because that direction makes sense in the totality of the sailing they do. And there is no evidence that direction is particularly 'unsafe'. Just to quote from the official Sydney to Hobart report "There is no evidence that any particular style or design of boat fared better or worse in the conditions. The age of yacht, age of design, construction method, construction material, high or low stability, heavy or light displacement or rig type were not determining factors."
As to the expedition centerboards - that feature is primarily for the important task of being able to sneek into shallow enough water that truck size ice bergs can't follow you. They ground outside you. And for being able to take the ground well. It also DOES happen to make those boats (generally) run really well, with really good directional stability - which means they (generally) dont round up and they dont need to even test whether keels are a primary or secondary or contributing cause to roll overs. But, I would suggest it is rather clear that keels can and do have complicated hydrodynamic effects on capsize.
MikeJohns seems to like narrow/heavy/full keel/barn door boats and that's just fine. They can be fine boats. But they bring their own set of compromises. And they are NOT (at all) immune to breaking waves, and he continues to rather overstate what the tank testing determined. No-one (that I know) is 'against' RM or AVS - they just bring compromises. There are rather a wide range of people 'against' full keels and barn door rudders - but again they just bring compromises. Narrow vs Wide is honestly the most interesting discussion - there are great boats along that whole spectrum from pencil thin ones to square multihulls - all seaworthy.
Anecdotally, the only boat I know which has been knocked over (and then abandoned near S Georgia)) while streaming a series drogue was in this general (heavy/full/barndoor) design space - this happened primarily because it was a single hander trying to a solo RTW, who was just too fried and tired and was making mistakes. Which to my mind points out the more important contributing factors than boat design - skipper skill and knowledge and raw (bad) luck, and in the 'design space' raw size is the only thing (yea in the general middle of the design space, if you go to a corner of the space you can ofc create problems) which systematically effects outcomes (both in tests and empirically).
There's a common theme in these sorts of discussions where individuals try and subvert research. That research has been done for a long time. It's repeated and validated, it's not highly theoretical.
Of course skill can make up for deficiencies and compromises in vessel design.
No one has ever suggested anything about designers as you said "being morons" , but they they are designing for a commercial market that dictates the compromises.
Performance influences designers more than seakindliness or inate seaworthiness. Performace is more easily achievable with a light boat. There's nothing inately slow about a heavy boat. It's the sail area ratios and the power to carry sail that determine speed. But heavy boats performance are expensive to produce......
For example, design trends; you use the terminology "a Barn Door" for a lower aspect rudder. That a lower aspect rudder stalls at much higher loads than a high aspect rudder. But a high aspect rudder has a more desirable lift/Drag ratio and a lower wetted surface area.
If you ask for the most seaworthy controllable hullform they will or should design something else. Because they design they design a Pogo and they are skilled qualified designers doesn't mean the design trend is necessarily desirable.
Seaworthiness and seakindliness especially aren't current trends in the majority of production boats.
The plumb stem is a really good illustration of current trends.
As for the 1998 S-H the outcome was well predicted by the research done on the Fastnet. It's a pretty clear example of people misled about the level of safety of the boats they are buying.
Just look at the data. There was a clear trend of the less seaworthy boats being rolled ( fully inverted) and the more seaworthy boats coping very well.