No, it isn't a weak point. I have no doubts it is possible to break, but it's almost unheard of. If DocSavage really has broken multiple hooks he has broken a few mirrors, and crossed paths with a lot of black cats. The problem with a link as you suggest is that there is no good way to capture said pin without it being a major issue to install. There is no new design links. Ruger has been using the same hammer links since 1979, since there is nothing wrong with them. Hopefully Outpost can give some more experienced and accredited thoughts on the matter.
There isn't really anything I can think of reliability wise that effects the Redhawk that doesn't also effect any other revolver. The phrase "revolvers handle neglect well, but not abuse. Semi-auto's handle abuse well, but not neglect" is as true as they come. The failure you had is very rare, and is certainly a case of pushing neglect too far. Parts breakages simply aren't a problem in Redhawks. About the only thing I can think of that sometimes effects Redhawks is their firing pin protrusion is a little short, some can have issues using certain primers. Surely you would have noticed that issue in the last 30 years if yours had that issue. It's not really an issue with firing pin protrusion either, it's more an issue with not making good contact with the transfer bar. It can be fixed fairly easily, but again yours does not have that problem.
Speaking of transfer bars, I forgot to mention that in my post to LeonardC if you shorten the sear to reduce creep in any Ruger, you also run the risk of not raising your transfer bar enough. The fix for that is to slightly grind down the stop on the nose of your hammer about .020" which can be done with a simple homemade jig and a belt or disc grinder. Or just don't do that, and live with a little trigger creep. I like my triggers really crisp, and I've not had this issue yet, but it can happen.