I am really surprised this didn't kick up

You fell into exactly the same trap as Tony. The factory engineering becomes irrelevant the moment you change the load inputs beyond what the factory intended. If you change the load parameters you can't assume the factory design will work as intended. If you want to run around on bias ply's with /6 torsion bars that's fine, but if you don't you'd better re-evaluate the situation.

My personal point of view is that I'd rather have the car flex where it won't hurt anything instead of risk damage by altering the fundamental design of the vehicle.

That said, I also said I'd still consider subframe connectors for my car.

Why do I ride that fence? Because I feel that the factory engineering for a pass-car of the sixties was suitable for those roads and conditions (as you allude to) at the time. And I'm in agreement with you that inputs have changed, both internal and external to the vehicle. And as always, end use is the primary concern. You're not exactly using your car in a manner that Chrysler engineers of the time would have considered "statistically significant", just like Ricky Roadracer or Davy Dragracer.

Again, I make no comment to suitability. Just an explanation of why the factory did it the way that they did. Obviously, they had their reasons, and we have reasons we don't do it that way now.