How about a different tack? I strive for self reliance above all else. In the abstract that focuses more on self recovery (winch, high lift, etc.).
Looking deeper, though, many of these items are going to be based on experience with your individual vehicle and driving style. For example, the D35 in the back of the YJ was supposed to be total junk and very fragile. Multiple runs through the Rubicon, most all of the 4+ trails in Moab, all sorts of stuff in CO (including a trail aptly named "Carnage") had me snapping one shaft. And the reason for that was crappy driving by me and inappropriate gearing for the tire size.
However, I made sure that I carried as many spares as relevant to my driving: U joints, yokes, drank and rear driveshafts, steering components, etc., in addition to all the tools to perform those repairs (including an on board air system allowing me to run air tools).
My point is that I could fix any of the weak links that could have broken and the only thing I was missing was a welder. Therefore, experience tells you what may be possible to be prepared for (i.e. weak links in the drivetrain) and I don't necessarily think "beefing" those components will keep you out of trouble. Having the tools and spares to sort it out no matter what would be more important in my opinion. Now this makes carrying cool guy stuff like a refrigerator and big propane stove and such a little harder, but then that gets into the use case of the type of travel that is going to be done.