i don't know if anyone has suggested this yet but how about,making it so on a car with a carburetor you need to pump the throttle before starting the engine
That's a pretty steep slope for the devs to slip down. For now, all cars run "optimally" along with tires, so everything runs perfect. For example, the tire grip is already calculated at the optimal temperature, hence why if they added tire thermals, tires would perform even poorer.
