I agree that telemetry comparisons and testimonies from professional drivers don't exactly prove anything. But I agree with
@nrosko that it would be good for SMS to elaborate upon details of the physics and various simulations, not to convince the skeptics, but for people who would want to know about those things but have not been following the game closely like we do in this forum. I don't think many people knew how much PCARS1 had going on under the hood.
I think it would be great to have a brief video showing off some of the details like the atmospheric modelling and volumetric throttle simulation, or an overview of all the components that track temperature and wear. Particularly the things that are uncommon or unprecedented among sims, like parts of LiveTrack 3.0 and the dynamic surfaces.
If SMS had the resources to do a real life comparison video like Enthusia's Data Comparison trailer, that could be nifty too.