Honestly, it's hard to tell if Dan G. is a car guy. If you listen to all the videos he talks in, he sounds like a sham. My main complaint with the last few iterations of the forza series is that they seem to be completely marketing driven and focus on flash over substance.
Weather, night time, temperature, equipment failure, pre-race briefings, track instruction, etc ... Forza keeps leaving out key real elements of racing in favor of racing around a sterilized idea of perfection over and over again. In fact, it's rather boring ... all the changes and imperfections of real racing environments are what adds the difficulty and makes it interesting.
Gran Turismo is sometimes a mess, but you can tell the creator loves cars. I hope the next gen hardware makes it possible to simulate a lot of the above stuff. If they use the hardware to create an "even better AutoVista", I'll silently scream.