I think the problem with the issue....is that we haven't got any high mileage 347's running around to prove that there aren't any longevity problems with the rod ratio. So, as much as you say there's no proof of their being any longevity issues with the 347, there really isn't any proof to support the opposing argument either?
IMO, the concerns are sound. Steeper rod angles will create more side load and as a result, increased wear. That is a fact, it's not a "theory", that's mechanical engineering, practical geometry and applied physics. The question is....will it be enough of a side load increase and enough wear to make a difference in the long run? That’s something that can be theorized, but can’t be proved, or disproved without long term testing. And nobody seems to have made it that far yet?