I particularly found interesting his assertion of the change on the Gen2 from 5w30 to 5w40, in specific, because the reasoning provided is illogical.The weight/viscosity of oil you run is specific to things like bearing clearance, crank/rod/main material composition, and operating temperature, etc. Finding the "proper" oil for your application is a combination of all of that and more.
It stated in the reasoning letter that they wished to increase the film strength to alleviate bearing failures - by hydrodynamics has proven that you have increased load capacity with thinner oil and tighter clearances - which means the reasoning is counter-intuitive to what will happen.
I heard once, in a class on the engine, that the scuttle-butt behind that, was that the thicker oil would act as a crankshaft damper, reducing the harmonics induced under high load, low RPM operation, due to an increase in the windage cloud! Supposedly, the crankshaft was hitting a resonant frequency that was causing enough deflection to hit the bearings....
But I doubt he understands enough about hydrodynamics to understand what was just stated! Like people assuming Red Line 70 weight Top Fuel oil is 70 weight, cause it’s better ... the fuel dilution ensures it’s 20 weight, or thinner, when the engine is at it’s highest load peaks.... that’s the ONLY reason it’s formulated that thick.