You seem to have had more problems than most have.

A stock rod breaking....that is possible, that is why we generally polish and grind the sidebeams. Are you sure a bearing didn't get tight?

As far as a bad spring....that is not even close to being the fault of engine design. Valve float is caused by overrevving it, the wrong spring for the application, or a faulty or worn out part. That is why you keep after that stuff in a race car. Any race car.....any type of engine.

You still are not going to convince me that a Hemi is an unreliable piece, if built and raced correctly. If not, no design will survive. I have forty years of racing them that says you are wrong.