ATLD,
I don't think bad machines are designed by bad engineers. I think bad machines are produced in America, because engineers are controlled by over paid executives with their head up their ass. They are more worried about share holders than producing a good product. I shy away from American products when possible except for ones that I know produce quality and will respond to consumer questions. I have tried to contact some companies and have ended up in an endless loop without ever getting to talk to someone. As an example I have a nice little $350 compressor in my home garage. The $11.00 plastic fan broke. I have the instructions with part #s. I called Campbell Hasfeld to order the part. I was informed that that division was sold off to Devilbliss. I finally get ahold of Devilblis only to be informed that the compressor division has been sold off to Porter Cable. I finally get ahold of Porter Cable only to be told that that product has been dropped. I now have a useless $300.00 compressor, because of an $11.00 plastic fan. I'm supossed to boost the economy and buy a new unit. IT'S THE AMERICAN WAY. This wouldn't happen in Europe. There are a few quality U.S. companies that I am aware of: Bose, Delta Faucets, Royal Vacuums, Binks Sprayers, and Ruger Firearms.
You may have some merit in your point about the brittle rails. If that is so I would recommend replacing only the inside rail on the left head. That is the only one that breaks. In my 30 years this has been my experience.
I believe your fears are unfounded on the clips, but if it makes you feel better, you can lightly peen the master link even with the clips on.