Agreed! Gamers already won't do 2-3 hour races like the pros do and have you heard them holler when they're stuck behind a safety car for 3 laps? Expecting them to follow other bits of real life just won't happen if its mandatory... any of the realism upgrades in gameplay will have to be optional.
I think these advanced thermals should be part of every sim. Ah btw I discovered how the old windshield of trucks distort the outside world when you looking out from cockpit view in the new Spintires Mudrunner Not to mention GT3 cars are "first rides" for a lot of racers if they're rich enough. If you have several million dollars burning a hole in your wallet and a freshly issued competition license, you can buy a turnkey GT3 or GT4 car and go racing with it in various clubman series. Those swarms of 911s in the lower classes of '90s sports car races weren't big teams with star driving talent, they were a bunch of fairly ordinary people with Porsches and lots of money to spend. And this was doubly true with old-school racing where "gentleman" (i.e. a rich guy with little prior experience but enough money to buy a race car) racers predominated. The extreme difficulty people imagine and the vast amount of experience required seems mostly true for open-wheel and prototype racing. A GT3 or GT4 car is designed to help you go fast and to keep you alive.
Thats cool and all but then we wouldnt talk about "sim racing" anymore. It would be so much work to get all that as realistic as possible that the devs would never be finished.1. As a gamer I want to have a simple track builder, so I can race on any road in-game I want.
A good easy track builder. Create your own tracks using Google maps for example.
Height differences and track length+width for example can be reasonably accurate then.
You can edit parts you want, add trees whatever. And suddenly the road in front of your home is a track or practice location
2. As a gamer I want to buy every car and engine type in a game. So I can drive exactly my own car in a game. I want to be able to upgrade it accordingly
If you add a car to a game, add all the types as a developer. I mean in engine choice, luxury trim etc.
If you're poor in-game or want to tune you may buy the base version of a car. If you want a fast car immediately you buy the better car.
So for example, add a Ford Focus.
Base model is an 1.0 ecoboost, but you can also buy a diesel, an ST, RS whatever. You could even completely rebuild your own car...
I mean, you can always drive the fastest type in a game. But why not a base model?
For some "simpler" racing game i think Gran Turismo have much of that? Not the track builder, but in sim racing we are often very picky and want the tracks as close to reality as possible - down to the bumps, angles, cambers etc. 
